View-reactions sheet doesn't update immediately when reactions change #1747
Description
In our initial implementation for #740, the view-reactions sheet doesn't update immediately when the message's reactions change. Ideally, it would; this issue is to accomplish that.
Implementation
As an optimization, PerAccountStore doesn't notify listeners when a message's reactions change. Probably, the view-reactions sheet should listen to the MessageListView (which does), or there should be a way to listen for changes on one particular message (including notifications when the message is deleted).