[lib] added reaction type to local unshim types

Summary:
added reaction type to local unshim types. This is so reaction messages will now be unshimed with the rest of new message types introduced throughout the years

Linear Task: ENG-2247

Depends on D5805 and D5752

Test Plan:
I was able to get messages to render correctly on the UI. This makes me feel very confident that this works as expected

Reviewers: atul, tomek, rohan

Reviewed By: atul, tomek, rohan

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D5817