Enable ESB thresholds feature by default.

This is part of the release for Client Side Phishing model using the ESB thresholds. The finch field trials has been removed from a previous change list.

Bug: 1406979
Change-Id: Iadcce4bde653320baba76578493fe462e933a452
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4573919


Reviewed-by: Xinghui Lu <xinghuilu@chromium.org>
Commit-Queue: Seung Jae Lim <andysjlim@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1152628}