[native] Force the tooltip to the bottom of the pinned messages screen

Summary:
Fixes the second part of ENG-3959, where the tooltip was weirdly placed and reactions were cut off.

Depends on D8098

Test Plan:
See the updated video and screenshot below

Reviewers: kuba, ginsu

Reviewed By: kuba, ginsu

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8099