Protective Audience: Move CreativeInfo from TrustedSignals

Move CreativeInfo into content/services/auction_worklet/public to make
it easier to move TrustedSignalsUrlBuilder out of
TrustedSignalsRequestManager and into
content/services/auction_worklet/public, so that I can use it to
initiate trusted bidding signals requests in the browser process.

Change-Id: Iba678cd44246a38d2d72dd1beacb2bb03559de9d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6512617
Commit-Queue: Abigail Katcoff <abigailkatcoff@chromium.org>
Reviewed-by: Joe Mason <joenotcharles@google.com>
Reviewed-by: mmenke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1456926}