using uuid and datetime [LET-5508] (#5430)

* using uuid and datetime

* add run_id

---------

Co-authored-by: Ari Webb <ari@letta.com>

tests/integration_test_send_message_v2.py

@@ -36,7 +36,7 @@ from letta_client.types import (
 from letta.log import get_logger
 from letta.schemas.agent import AgentState
 from letta.schemas.enums import AgentType, JobStatus
-from letta.schemas.letta_ping import LettaPing
+from letta.schemas.letta_message import LettaPing
 from letta.schemas.llm_config import LLMConfig
 
 logger = get_logger(__name__)