Introduced a new case to `reduceMessageStore` which was when the `sendReactionMessageActionTypes` success type gets dispatched. Like a lot of the other cases in `reduceMessageStore` when this case is true, it returns the new message store with the merged messages in them, so in this case the newly created reaction message
---
Depends on D5780
Linear Task: [[ https://linear.app/comm/issue/ENG-2246/liking-a-message | ENG-2246 ]]