Part of the way we want to alert clients that a message has been pinned / unpinned is by introducing a new message type and message spec to represent toggling a pin. I've decided to consolidate the
two actions into one spec and handle the robotext / notif texts that are sent within the functions to avoid lots of duplicate code (much like `update-relationship-message-spec.js`).
Depends on D7112
Linear: https://linear.app/comm/issue/ENG-3190/introduce-a-new-message-type-and-spec-for-toggling-pins