fix(tests): fold the local price map into the provider model sets

CI unit shards load the price map from main at import, so a model that only
exists on the branch never reaches open_ai_chat_completion_models and
cost_per_token cannot infer its provider. Refresh the sets after swapping in
the local map so the tier pricing cases resolve gpt-6-astra before merge

tests/test_litellm/test_openai_service_tier_long_context_pricing.py

@@ -69,6 +69,7 @@ NO_PUBLISHED_PRIORITY_LONG_CONTEXT = ("gpt-5.4", "gpt-5.5")
 def _local_model_cost_map(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setenv("LITELLM_LOCAL_MODEL_COST_MAP", "True")
     monkeypatch.setattr(litellm, "model_cost", litellm.get_model_cost_map(url=""))
+    litellm.add_known_models()
 
 
 @lru_cache(maxsize=2)