Add-ons Conversation Improvements by Xon 2.5.1

• When using XenForo Enhanced Search:
  • Improve reliability of indexing recipients into conversations for search
  • Improve generating constraint restricting conversations to recipients
  • If using Search Improvements v2.9.6 or earlier, ensure the option "Push "View X by others" check into XFES" is enabled.
    If it was disabled, you will need to re-index for conversation search to return results

• Fix SQL error when the last member of a conversation leaves

• Require XenForo 2.2+
• Improve handling of leaving/joining conversation and the impact on search.
  This will require re-indexing conversation messages.
  • When a user joins a conversation, ensure they can search that conversation
  • If a user leaves a conversation, do not return it in search results.