personalization: dynamic color test

Added a test that makes sure colors change when clicking the toggle.
I also updated the formatting.

BUG=b:281732306
TEST=browser_tests PersonalizationApp*DynamicColorEnabled

Change-Id: Id8af667a9ea2205b16cb2b35985bbc4f3883413e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4540243


Commit-Queue: Erica Lee <ericamlee@google.com>
Reviewed-by: Jeffrey Young <cowmoo@google.com>
Cr-Commit-Position: refs/heads/main@{#1147423}