Requirements_cache shouldn't create a cache folder when skipped. (#31961)

* If the requirements cache is skipped then we shouldn't generate a requirements_cache folder.

* pre-commit

---------

Co-authored-by: eddiephillips <[email protected]>

Author: eddiep24

sdks/python/apache_beam/runners/portability/stager.py

@@ -214,7 +214,8 @@ def create_job_resources(options,  # type: PipelineOptions
           os.path.join(tempfile.gettempdir(), 'dataflow-requirements-cache') if
           (setup_options.requirements_cache is None) else
           setup_options.requirements_cache)
-      if not os.path.exists(requirements_cache_path):
+      if (setup_options.requirements_cache != SKIP_REQUIREMENTS_CACHE and
+          not os.path.exists(requirements_cache_path)):
         os.makedirs(requirements_cache_path)
 
       # Stage a requirements file if present.