antlir: Go back to omnibus linking for centos10

Summary: Until we can get native python + third-party/python working with centos10 distro platform

Test Plan:
Antlir distro python toolchain tests pass:
https://www.internalfb.com/intern/testinfra/testrun/13510798996319307

Can run orchestrator in a c10 container (as ominbus):
```
$ buck run fbcode//mode/opt -c fbcode.platform010_cuda_version=12.8 --target-platforms fbcode//antlir/distro/platform:centos10-x86_64 fbcode//tee/orchestrator/server:install[container]
File changed: fbcode//tee/orchestrator/server/BUCK
Buck UI: https://www.internalfb.com/buck2/b1657ff3-d24d-467e-8549-e84b5f03c81e
Network: Up: 16MiB  Down: 714MiB  (reSessionID-4712d9bc-6cdd-421b-b09c-914888f08334)
Loading targets.   Remaining      0/45869                                                                                                       118084 dirs read, 1539130 targets declared
Analyzing targets. Remaining      0/186629                                                                                                      917903 actions, 1003562 artifacts declared
Executing actions. Remaining      0/184711                                                                                                      1:58.3s exec time total
Command: run.      Finished 166 local, 1 cache (1% hit)                                                                                         2.5s exec time cached (2%)
Time elapsed: 1:29.6s
BUILD SUCCEEDED - starting your binary
bash-5.2# /usr/local/bin/orchestrator --help
ERROR    2025-09-25 07:57:14,026 NoPIIStructuredLogger:39 uncategorized: [ORCHESTRATOR_ALLOWED_LOG_START] {"event_type":
         "tee_tokenizer", "event_message": "Unable to load tokenizer"} [ORCHESTRATOR_ALLOWED_LOG_END]
ERROR    2025-09-25 07:57:14,054 NoPIIStructuredLogger:39 uncategorized: [ORCHESTRATOR_ALLOWED_LOG_START] {"event_type":
         "tokenizer_registry", "event_message": "Failed to load default tokenizer tiktoken_v5"}
         [ORCHESTRATOR_ALLOWED_LOG_END]
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/usr/local/bin/orchestrator/__main__.py", line 985, in <module>
  File "/usr/local/bin/orchestrator/__main__.py", line 982, in __invoke_main
  File "/usr/local/bin/orchestrator/__main__.py", line 597, in main
  File "/proc/self/fd/3/__par__/meta_only/bootstrap.py", line 111, in run_as_main
  File "/proc/self/fd/3/__par__/bootstrap.py", line 75, in run_as_main
  File "/usr/lib64/python3.12/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 999, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/proc/self/fd/3/tee/orchestrator/server/main.py", line 9, in <module>
  File "/proc/self/fd/3/tee/orchestrator/orchestration/request_handlers/request_handler_registry.py", line 8, in <module>
  File "/proc/self/fd/3/tee/orchestrator/orchestration/request_handlers/action_suggestions_request/handler.py", line 14, in <module>
  File "/proc/self/fd/3/tee/orchestrator/orchestration/llama_stack_impl/agent_runner.py", line 20, in <module>
  File "/proc/self/fd/3/tee/orchestrator/orchestration/utils/request_utils.py", line 32, in <module>
  File "/proc/self/fd/3/tee/orchestrator/orchestration/utils/tee_tokenizers/tokenizer_registry.py", line 109, in <module>
  File "/proc/self/fd/3/tee/orchestrator/orchestration/utils/tee_tokenizers/tokenizer_registry.py", line 41, in __init__
  File "/proc/self/fd/3/tee/orchestrator/orchestration/utils/tee_tokenizers/tokenizer_registry.py", line 50, in _load_default_tokenizers
  File "/proc/self/fd/3/tee/orchestrator/orchestration/utils/tee_tokenizers/tee_tokenizer.py", line 58, in __init__
  File "/proc/self/fd/3/tee/orchestrator/orchestration/utils/tee_tokenizers/tee_tokenizer.py", line 48, in __init__
  File "/proc/self/fd/3/tee/orchestrator/orchestration/utils/tee_tokenizers/tee_tokenizer.py", line 71, in _get_local_tokenizer_file_path
ValueError: Resource path for 'tiktoken_v5' not found or doesn't contain tokenizer.json.
```

Reviewed By: CookieComputing

Differential Revision: D83229386

fbshipit-source-id: 665e92d781bd58924f5ff597f2e7134e4c7a4aa3

Author: get9

antlir/antlir2/bzl/python_helpers.bzl

@@ -31,12 +31,25 @@ def _extract_python_library_info(target) -> PythonLibraryInfo | None:
         return library_info.get(PythonLibraryInfo)
     return None
 
-def _extract_par_executable_info(target) -> DefaultInfo | None:
+def _extract_native_python_executable(target) -> DefaultInfo | None:
     """
     Extracts the par executable from a target. For native python this is the actual
     native executable that doubles as the interpreter.
     """
-    return target[DefaultInfo].sub_targets.get("native-executable", {}).get(DefaultInfo)
+    native_executable = target[DefaultInfo].sub_targets.get("native-executable")
+    if native_executable:
+        return native_executable[DefaultInfo]
+    return None
+
+def _extract_omnibus(target) -> DefaultInfo | None:
+    """
+    Extracts libomnibus output (if present) from a target. Only relevant if the python
+    binary was linked with omnibus linking.
+    """
+    omnibus = target[DefaultInfo].sub_targets.get("omnibus")
+    if omnibus:
+        return omnibus[DefaultInfo]
+    return None
 
 def extract_par_elfs(target) -> list[Artifact]:
     """
@@ -62,10 +75,8 @@ def extract_par_elfs(target) -> list[Artifact]:
             if isinstance(shlib.lib.output, Artifact)
         ])
 
-    par_executable_info = _extract_par_executable_info(target)
-    if par_executable_info:
-        exe = par_executable_info.default_outputs
-        if exe:
-            elfs.append(exe[0])
+    for info in (_extract_native_python_executable(target), _extract_omnibus(target)):
+        if info and info.default_outputs:
+            elfs.append(info.default_outputs[0])
 
     return elfs

antlir/antlir2/os/oses.bzl

@@ -101,7 +101,7 @@ OSES = [
             "antlir//antlir/antlir2/facebook/flavor/centos10:corp": "antlir//antlir/antlir2/facebook/images/build_appliance/centos10_corp:build-appliance",
         }),
         # TODO(T238134086): This should point to the third-party/python interpreter when we've verified this correctness.
-        python = new_python_t(interpreter = "/usr/bin/python3.12")
+        python = new_python_t(interpreter = "/usr/bin/python3")
     ),
 ]