Remove experimental flags for FamilyInfoFeedbackSource post launch.

Bug: 1324946
Change-Id: I80b7654e64c07e0d070a29c430ac9d9f6cec3937
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4026166


Commit-Queue: Nohemi Fernandez <fernandex@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/main@{#10715562}