[CI/Build] Fixed a test for invalid CLI argument validation in test_cli_args.py
https://github.com/vllm-project/vllm/pull/46779
https://github.com/vllm-project/vllm/pull/46779
https://github.com/vllm-project/vllm/pull/46793
Fixed exception handling for backslash escapes in `make_valid_python`