[0.84] Remove HomeUIA snapshots (#15921)

The HomeUIA snapshots do not provide much useful test coverage, and
cause a lot of churn on the test snapshots. Removing them to make
snapshot changes less ignorable.

Resolves the ±1px height drift on Appearance / AppState tabs by
removing the test that flaked on it.

(cherry picked from commit 08ad79f)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: vmoroz