[native] Convert ChatThreadListSearch to Reanimated 2 syntax

Summary:
Addresses ENG-8148.

Note that I replaced animateTowards with something more simple. The difference is the animation is reversed while partway through, it will still take the same length as if it was started from an end state.

Test Plan: On both iOS and Android physical devices, tested ChatThreadListSearch to confirm no functionality regressed.

Reviewers: inka

Reviewed By: inka

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D12166