Allow unauthenticated users to use the conversations endpoint

[sahilds1]

This ticket is a follow on to #309

[StubberG3]

Modify these endpoints to make JWT optional instead of required.

/chatgtpt/conversations
/chatgpt/continue_conversation

If the user is logged in -

• No changes needed. Continue to save and retrieve the conversations from our database.

If the user isn't logged in -

• Don't save any conversations to the database.
• Ensure that conversations from logged in users aren't shown.
• Modify endpoints on frontend & backend as the ID will no longer be the same the integers retrieved from the database (Consider uuid, a "public" string, etc")

[sahilds1]

The chatbot's been updated (#345 ) and isn't using the conversations endpoint right now (#380)

This ticket can be worked on as part of #380 and I filed a separate ticket to the make the current chatbot public