[Bugfix] Fix broken test_parse.py after _WrappedParser removal

[sfeng33]

Summary

• test_parse.py still imported _WrappedParser, which was removed in [Refactor] Remove dead code from parser infrastructure #44279. Updated to use DelegatingParser with a local subclass, matching the pattern already applied in test_streaming.py.
• Added vllm/parser/ to source_file_dependencies in the async-engine-inputs-utils-worker-config-cpu CI job. This was missing, so changes to vllm/parser/ source code didn't trigger the job that runs pytest -v -s parser, which is how [Refactor] Remove dead code from parser infrastructure #44279 merged without catching the breakage.

Test plan

• pytest tests/parser/test_parse.py -v — all 14 tests pass