Tested across `web` and `native`:
1. Pinned a message
2. Sent enough messages so the message is not automatically loaded when the chat is opened and the user would have to scroll up to load it
3. Closed the app and re-opened it
4. Made sure I could see the pinned message in the pinned messages modal/screen
Besides this, I ran `yarn workspace lib test` to make sure my existing unit tests for this code didn't break. I can alternatively add more unit tests in `message-utils.test.js` if needed for other message types
Also made sure to do this testing on the current state of `master` to repro the issue
Addresses [[ https://linear.app/comm/issue/ENG-6009/pinned-messages-dont-work | ENG-6009 ]]