Enable NetworkAnnotationMonitoring on ToT

Following finch rollout steps, enable NetworkAnnotationMonitoring
feature on ToT and remove from trial config. 100% stable rollout to
follow.

Also update unit test accordingly.

Bug: b:376122555
Test: out/Default/unit_tests --gtest_filter='NetworkAnnotation*'
Test: out/Default/browser_tests --gtest_filter='All/NetworkAnnotationMonitor*'
Change-Id: Ieeb1348778a58431b3c2fffc5b0b49a0916694ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6758152
Reviewed-by: Theresa Sullivan <twellington@chromium.org>
Reviewed-by: Chris Mullins <crmullins@chromium.org>
Commit-Queue: Aiden Chiavatti <chiav@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1490427}