fix: Ensure dummy API keys are set for tests with no_mock_provider marker

The test failures in CI were caused by tests with @pytest.mark.no_mock_provider
that prevented dummy API keys from being set. In CI with no real API keys,
this led to 'Model not available' errors.

Changed pytest_collection_modifyitems to always set dummy keys if missing,
regardless of markers. This ensures tests work in CI while still allowing
real API keys to be used when present.

Fixes test_conversation_field_mapping.py failures in CI across Python 3.10-3.12.

tests/conftest.py

@@ -88,15 +88,9 @@ def pytest_configure(config):
 
 def pytest_collection_modifyitems(session, config, items):
     """Hook that runs after test collection to check for no_mock_provider markers."""
-    # Check if any test has the no_mock_provider marker
-    for item in items:
-        if item.get_closest_marker("no_mock_provider"):
-            config._needs_dummy_keys = False
-            break
-
-    # Set dummy keys only if no test needs real keys
-    if config._needs_dummy_keys:
-        _set_dummy_keys_if_missing()
+    # Always set dummy keys if real keys are missing
+    # This ensures tests work in CI even with no_mock_provider marker
+    _set_dummy_keys_if_missing()
 
 
 @pytest.fixture(autouse=True)