[native] default selectMultipleEmojis to false for emoji keyboard

Summary: As I was working on the inline engagement redesign, I noticed some strange behavior with the emoji keyboard showing the already selected emoji when selecting a new emoji. This diff fixes that issue

Test Plan:
Emoji keyboard now works as expected

Reviewers: atul, kamil

Reviewed By: kamil

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8319