Currently, if a message is pinned, a toggle_pin robotext message appears in chat. This is how we determine whether a message's status is 'pinned' or 'unpinned' in order to display the appropriate
action for the user if they want to toggle that. The problem with this is that if a message is not fetched when the chat is loaded, then when the message results modal is opened, the pinned message doesn't
have the right information and will always be unpinned until the chat is scrolled up enough.
This diff modifies `fetchRelatedMessages` to include all messages of the `TOGGLE_PIN` type, so we know what messages should be pinned when creating the `ChatMessageItem`s in `chat-selectors`. Since these are
actual, visible messages I also had to filter them out of the view in `message-results-modal` and `message-results-screen` on `web` and `native`.
The last thing done is here a quick rename to update the callsites since we're now including pinned messages, so I've renamed `isMessageSidebarSourceReactionOrEdit` to
`isMessageSidebarSourceReactionEditOrPin`. I can also do this rename in a separate diff if it's too complicated to review the changes.
Resolves [[ https://linear.app/comm/issue/ENG-4671/pin-action-appears-for-message-in-pinned-messages-modal | ENG-4671 ]]