BUG: guidance engine - no reset of expired conversation

[renehonig]

Describe the bug
As a user of the guidance engine, I want to be clear whether my query is part of an ongoing conversation or the start of a new conversation. If it is part of an ongoing conversation, I want the original conversation to be displayed in the chat window. If the chat window if empty, i want my next query to be treated as a new conversation

Currently when a user comes back to the chat window after a previous conversation without giving (the very hidden) clear chat command, the guidance engine threats the next query as part of an ongoing conversation (even if the previous conversation was days ago). This leads to unpredictable answers and hampers the guidance engine performance.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'chat window'
2. Ask a query
3. Wait a long time
4. Login from a different browser
5. Go to 'chat window'
6. Ask another query
7. Check that this query is treated as an onging conversation in Langsmith

Expected behavior
When the chat window is empty, I expect my next query to be the start of a new conversation