refactor(api): enhance request handling and time management

- Initialized `response` variable in `trigger.py` to ensure proper handling in the trigger endpoint.
- Updated `http_parser.py` to conditionally set `CONTENT_TYPE` and `CONTENT_LENGTH` headers for improved robustness.
- Changed `datetime.utcnow()` to `datetime.now(UTC)` in `sqlalchemy_workflow_trigger_log_repository.py` and `rate_limiter.py` for consistent time zone handling.
- Refactored `async_workflow_service.py` to use the public method `get_tenant_owner_timezone` for better encapsulation.
- Simplified subscription retrieval logic in `plugin_parameter_service.py` for clarity.

These changes improve code reliability and maintainability while ensuring accurate time management and request processing.

api/core/plugin/utils/http_parser.py

@@ -86,10 +86,14 @@ def deserialize_request(raw_data: bytes) -> Request:
     }
 
     if "Content-Type" in headers:
-        environ["CONTENT_TYPE"] = headers.get("Content-Type")
+        content_type = headers.get("Content-Type")
+        if content_type is not None:
+            environ["CONTENT_TYPE"] = content_type
 
     if "Content-Length" in headers:
-        environ["CONTENT_LENGTH"] = headers.get("Content-Length")
+        content_length = headers.get("Content-Length")
+        if content_length is not None:
+            environ["CONTENT_LENGTH"] = content_length
     elif body:
         environ["CONTENT_LENGTH"] = str(len(body))