[native] Make ChatThreadList items dim whole row on hold

Summary: I noticed that when pressing a sidebar row in the ChatThreadList, the whole row wouldn't dim, just the part around the sidebar row. This diff makes the whole row dim.

Test Plan: I tested iOS and Android, in dark mode and light mode. I tested press down on each

Reviewers: palys-swm

Reviewed By: palys-swm

Subscribers: KatPo, zrebcu411, Adrian, atul, subnub

Differential Revision: https://phabricator.ashoat.com/D911