[Obs AI Assistant] Archiving conversations

[viduni94]

A user should be able to archive a conversation in their conversation list.

• The chat interface should include an option to archive conversations
• Anybody can archive system conversations
• Private conversations can be archived by the user who owns it
• Shared conversations can be archived by the user who owns it
• Archiving a shared or a system conversation will archive the conversation for all users
• Archived conversations are moved to a separate archived section (They don't appear in the conversation list)
• The "Archived" section is easily accessible from the main chat interface
• Archived conversations can be forked into new conversations --> These will be private to the user who forks it (Forking conversations are handled in [Obs AI Assistant] Forking conversations #209382)
• Archived conversations maintain the same visibility they had before archiving.

Figma Design - https://www.figma.com/design/Qr30UGLnJgk4BwPBjYxm2Y/%5Bo11y%5D-Conversations-management?node-id=2001-83555&t=w8q3GrflPl7b52oZ-1

Dependencies

Preview Give feedback

1. [Obs AI Assistant] System conversations #180710
   Team:Obs AI Assistant +1
   
2. [Obs AI Assistant] Forking conversations #209382
   0 of 1
   Team:Obs AI Assistant +1
   
3. [Obs AI Assistant] Sharing conversations #206590
   0 of 1
   Team:Obs AI Assistant +1
   

[elasticmachine]

Pinging @elastic/obs-ai-assistant (Team:Obs AI Assistant)