[native] Replace chat name with raw chat mention

Summary:
Solution for ENG-4553 and ENG-4555.

This diff adds support for chats in mentionTypeaheadTooltipActions . Chat entry is encoded in the following convention:

@[[chat_id:default_text]]

Depends on D8908.

Test Plan: Tested later in the stack.

Reviewers: tomek, inka, rohan

Reviewed By: inka

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8909