fix(test): increase server wait time and add retry to flaky external API tests

- test_basic_python_version.py: increase server startup wait from 60s to 90s
  for slower CI environments (fixes installing_litellm_on_python_3_13)
- test_a2a_agent.py: add flaky(retries=3, delay=5) for non-streaming test
  that depends on live A2A agent endpoint

Co-authored-by: Ishaan Jaff <ishaan-jaff@users.noreply.github.com>

tests/agent_tests/test_a2a_agent.py

@@ -25,6 +25,7 @@ def get_a2a_agent_url():
 
 
 @pytest.mark.asyncio
+@pytest.mark.flaky(retries=3, delay=5)
 async def test_a2a_non_streaming():
     """Test non-streaming A2A request."""
     from a2a.types import MessageSendParams, SendMessageRequest

tests/local_testing/test_basic_python_version.py

@@ -138,8 +138,8 @@ def test_litellm_proxy_server_config_no_general_settings():
             ]
         )
 
-        # Allow some time for the server to start
-        time.sleep(60)  # Adjust the sleep time if necessary
+        # Allow some time for the server to start (increased for CI environments)
+        time.sleep(90)  # Increased from 60s for slower CI runners
 
         # Send a request to the /health/liveliness endpoint
         response = requests.get("http://localhost:4000/health/liveliness")