Add WPT for registration and challenges from a third-party context

This CL makes sure that registration and challenge setting don't work
from a third-party context if all the bound cookies are first-party.

Fixed: 417410430
Change-Id: I0b9ce736cac5a36a71c55c11a515031a7c036ae1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6961315
Reviewed-by: thefrog <thefrog@chromium.org>
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1518764}