[native] Forward searchInputRef from ChatThreadList to ChatThreadListSearch

Summary:
Forward ref from ChatThreadList to ChatThreadListSearch... which will in turn forward it to the inner Search component.

Depends on D9208

Test Plan: Search experience continues to look and work as expected. Set logs in all expected callbacks to ensure that they fired as expected. Made sure that x-icon and "Cancel" button continue to look and behave as before.

Reviewers: tomek, ginsu, rohan

Reviewed By: tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D9209