Revert "Revert "feat: enable provider models persistence" (#6590)" (#6595)

tests/test_sdk_client.py

@@ -32,6 +32,7 @@ from letta.config import LettaConfig
 from letta.jobs.llm_batch_job_polling import poll_running_llm_batches
 from letta.server.server import SyncServer
 from tests.helpers.utils import upload_file_and_wait
+from tests.utils import wait_for_server
 
 # Constants
 SERVER_PORT = 8283
@@ -106,7 +107,7 @@ def client() -> LettaSDKClient:
         print("Starting server thread")
         thread = threading.Thread(target=run_server, daemon=True)
         thread.start()
-        time.sleep(5)
+        wait_for_server(server_url, timeout=60)
 
     print("Running client tests with server:", server_url)
     client = LettaSDKClient(base_url=server_url)