fix(event-handler): fix ruff lint violations in util.py docstrings

Update docstring parameter type hints to use modern Python 3.10+ syntax:
- List[Dict[str, List[str]]] -> list[dict[str, list[str]]]
- Optional[Dict[str, Any]] -> dict[str, Any] | None

Part of #8088

Signed-off-by: hirenkumar-n-dholariya <hirenkumarnd@gmail.com>

Author: hirenkumar-n-dholariya

aws_lambda_powertools/event_handler/util.py

@@ -74,9 +74,9 @@ def _validate_openapi_security_parameters(
 
     Parameters
     ----------
-    security: List[Dict[str, List[str]]]
+    security: list[dict[str, list[str]]]
         A list of security requirements
-    security_schemes: Optional[Dict[str, Any]]
+    security_schemes: dict[str, Any] | None
         A dictionary mapping security scheme names to their corresponding security scheme objects.
 
     Returns