fix: Resolve test isolation issues for o3-pro test

- Fixed test_fallback_with_shorthand_restrictions to clear restriction
  service singleton in finally block, preventing state leakage
- Updated o3-pro test to use @patch.dict for OPENAI_ALLOWED_MODELS,
  following standard pattern and allowing both o3-pro and o3-pro-2025-06-10
- Removed invalid cassette file that had wrong request content

The test now passes in both isolated and full suite runs.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/test_model_restrictions.py

@@ -694,3 +694,6 @@ class TestAutoModeWithRestrictions:
             registry._initialized_providers.clear()
             registry._providers.update(original_providers)
             registry._initialized_providers.update(original_initialized)
+            
+            # Clear the restriction service to prevent state leakage
+            utils.model_restrictions._restriction_service = None