fix: make attach/detach routes return None if sdk verion 1.0 (#6203)

* Revert "Revert "feat: make attach/detach routes return None if version is 1.0 [LET-5844]" (#6201)"

This reverts commit bb0d10725f5889306de61e1758f061d6c1041c52.

* fix type checking

* revert

* return state for blocks and sources

* func signatures

* create memgpt_agent for cloud-e2e-tests

* Revert "create memgpt_agent for cloud-e2e-tests"

This reverts commit f279e5897b0942b1006a5f8527713dd801064c63.

* fix

---------

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

tests/sdk_v1/test_sdk_client.py

@@ -460,8 +460,17 @@ def test_reset_messages(client: LettaSDKClient):
         # After reset, messages should be empty or only have default initial messages
         # Messages returns SyncArrayPage, check items
         assert isinstance(messages_after.items, list), "Should return list of messages"
-        assert isinstance(reset_agent, AgentState), "Should return updated agent state"
-        assert reset_agent.id == agent.id, "Should return the same agent"
+
+        # In SDK v1.0, reset-messages returns None, so we need to retrieve the agent to verify
+        if reset_agent is None:
+            # Retrieve the agent state after reset
+            agent_after_reset = client.agents.retrieve(agent_id=agent.id)
+            assert isinstance(agent_after_reset, AgentState), "Should be able to retrieve agent after reset"
+            assert agent_after_reset.id == agent.id, "Should be the same agent"
+        else:
+            # For older SDK versions that still return AgentState
+            assert isinstance(reset_agent, AgentState), "Should return updated agent state"
+            assert reset_agent.id == agent.id, "Should return the same agent"
 
     finally:
         # Clean up