Enable RedInterstitialFacelift on tip of tree

This includes adjusting an ios test that was using one of the old string
constants and adding the new interstitial strings to the webview string
allowlist. For more context, see go/red-interstitial-facelift-dd.

Bug: 1469647
Change-Id: I626e887cb1b03d9f48b4c1e2a3a2cb2325ebfa40
Binary-Size: Old strings will be removed from allowlist during code cleanup, reducing binary size
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5070680
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Reviewed-by: Bo Liu <boliu@chromium.org>
Reviewed-by: Daniel Rubery <drubery@chromium.org>
Commit-Queue: Sarah Krakowiak <skrakowi@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1231535}