doc: fix inconsistency between the docstring and the implementation of argument auto_batch_size of DeepEval with paddle and pytorch backend (#4865)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

* **New Features**
* Automatic batch size handling is now enabled by default when creating
a new DeepEval instance.

* **Documentation**
* Improved formatting consistency in model information and multi-task
training guides by removing unnecessary blank lines.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: glwan <wanguolin@dp.tech>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 3 people

deepmd/dpmodel/infer/deep_eval.py

@@ -62,7 +62,7 @@ class DeepEval(DeepEvalBackend):
         The output definition of the model.
     *args : list
         Positional arguments.
-    auto_batch_size : bool or int or AutomaticBatchSize, default: False
+    auto_batch_size : bool or int or AutomaticBatchSize, default: True
         If True, automatic batch size will be used. If int, it will be used
         as the initial batch size.
     neighbor_list : ase.neighborlist.NewPrimitiveNeighborList, optional

deepmd/pd/infer/deep_eval.py

@@ -58,7 +58,7 @@ class DeepEval(DeepEvalBackend):
         The output definition of the model.
     *args : list
         Positional arguments.
-    auto_batch_size : bool or int or AutomaticBatchSize, default: False
+    auto_batch_size : bool or int or AutomaticBatchSize, default: True
         If True, automatic batch size will be used. If int, it will be used
         as the initial batch size.
     neighbor_list : ase.neighborlist.NewPrimitiveNeighborList, optional

deepmd/pt/infer/deep_eval.py

@@ -83,7 +83,7 @@ class DeepEval(DeepEvalBackend):
         The output definition of the model.
     *args : list
         Positional arguments.
-    auto_batch_size : bool or int or AutomaticBatchSize, default: False
+    auto_batch_size : bool or int or AutomaticBatchSize, default: True
         If True, automatic batch size will be used. If int, it will be used
         as the initial batch size.
     neighbor_list : ase.neighborlist.NewPrimitiveNeighborList, optional