To use Reanimated's new layout animations we need to add libdefs for the different animations. This diff just handles the SlideInDown and SlideOutDown layout animations along with all the necessary classes/types needed to support these layout animations. I will annotate inline with where the changes/types came from.
Linear Task: ENG-2165
This approach seems to be overly complicated. Can't we just write a function that receives messageID, threadID and reaction? This function can be named after an action that is performed, so react or sendReaction.