feat: use copied replied message for showing reply block

[nikkothari22]

1. Added field for storing replied message block in a JSON field.
2. Patch added to migrate all existing messages to new structure
3. Reply blocks on web and mobile app now use the reply message's JSON instead of fetching the reply message block (perf 🚀). This alone cuts down multiple API calls when chats are loaded.
4. Reply blocks use the "content" field instead of the HTML field now. (Also perf 🚀). This means that the content would usually fit in a small section (lists would fit in one line for example).
5. Removed API to get reply message block content.
6. Removed truncated Tiptap editor on web app since it's not required anymore.

Also closes #608

Towards #446 and #472