Fix URL allowlist test due to youtube about page no longer under youtube.com domain

Change-Id: I971e9623786d70e3c068e547d8249e85bff0c049
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3445115


Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Xiang Ji <jxiang@google.com>
Cr-Commit-Position: refs/heads/main@{#968352}