[lib] add sendReactionMessageAction.started cases to message and local id reducers

Summary:
add sendReactionMessageAction.started cases to message and local id reducers. The message reducer handles adding the local reaction message to the message store, and the local id reducer handles incrementing the local id

Depends on D6122
Linear Task: ENG-2520

Test Plan:
Please watch the demo videos to see how the redux state changes when a sent reaction message action starts

Native:

Web:

Reviewers: atul, tomek

Reviewed By: tomek

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D6123