Add success toast notifications for chat room archive/unarchive actions

[coderabbitai]

Currently, the chat room archive/unarchive actions only show error toasts. To maintain consistency with other features in the app and improve user feedback, we should add success toast notifications.

Current behavior:

• Only shows error toasts when archive/unarchive fails

Proposed behavior:

• Show success toast when archive/unarchive succeeds
• Keep existing error toast for failures

References:

• Related PR: BA-2226 Three dot menu cleanup #210
• Comment:

Note: This enhancement was identified during code review but was not part of the original acceptance criteria.