Summary

This PR adds the missing optional-mode test (mirroring the existing test_security_oauth2_password_bearer_optional.py) and removes the now-unnecessary # pragma: nocover.

The fix

1. New test tests/test_security_oauth2_authorization_code_bearer_optional.py — auto_error=False, covering:
   • no Authorization header → returns None (handler returns the "create an account" message),
   • a valid Bearer token → returns the token,
   • a non-Bearer scheme → returns None,
   • the OpenAPI schema (unchanged from the existing auth-code test).
2. Remove the # pragma: nocover on the return None line, since the branch is now genuinely covered.

Notes

This is a coverage-consistency fix, not a behaviour change — fastapi/security/oauth2.py runtime behaviour is
unchanged; the PR only adds the missing test for an already-documented branch and drops the coverage-exclusion
pragma it was hidden behind.