fix(deps): update dependency fastapi to v0.123.9

Author: renovate[bot]

pyproject.toml

@@ -5,7 +5,7 @@ description = "BSS file server API"
 authors = [{ name = "Bence Csik", email = "22349790+csikb@users.noreply.github.com" }]
 requires-python = "==3.14.1"
 dependencies = [
-    "fastapi[standard-no-fastapi-cloud-cli]==0.123.7",
+    "fastapi[standard-no-fastapi-cloud-cli]==0.123.9",
     "pillow==12.0.0",
     # this should be part of standard-no-fastapi-cloud-cli, but is missing:
     # see: https://github.com/fastapi/fastapi/blob/6fae64ff49e8328048872714652a4dfa15406e41/pyproject.toml#L94-L98