fix: initialize result and run_status before try block in send_message (#9265)

Initialize `result` and `run_status` variables before the try block
to prevent UnboundLocalError in the finally block when exceptions
occur early in execution (e.g., during AgentLoop.load()).

Previously, if an exception was raised before `result` was assigned
inside the try block, the finally block would fail when trying to
access `result`, masking the original error with an UnboundLocalError.

This fix ensures the finally block can safely check and use these
variables regardless of when/where an exception occurs.

letta/server/rest_api/routers/v1/agents.py

@@ -1579,6 +1579,8 @@ async def send_message(
     await redis_client.set(f"{REDIS_RUN_ID_PREFIX}:{agent_id}", run.id if run else None)
 
     run_update_metadata = None
+    result = None
+    run_status = None
     try:
         agent_loop = AgentLoop.load(agent_state=agent, actor=actor)
         result = await agent_loop.step(