Cleanup red interstitial facelift omnibox/page info code

The red interstitial facelift feature has been launched on stable since
M121. Since the rollout has been a success for more than 2 milestones,
we can remove the flag and cleanup the code. This is the first CL, which
removes omnibox and page info changes.

Bug: b/294232396
Change-Id: I47d028ac8562c953e1318c5214cc893acf52b589
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5393669


Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Sarah Krakowiak <skrakowi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1280186}