[AsyncSB] Trigger CSPP ping when async check tracker has completed.

When async check is enabled, RT response may not be available in
cache_manager when the navigation is committed. This CL makes
ClientSideDetectionHost observe AsyncCheckTracker. When
AsyncCheckTracker notifies ClientSideDetectionHost that the check has
completed, it is guaranteed that RT response (if any) is stored in
cache_manager. ClientSideDetectionHost will trigger preclassification
at this point.

Add a histogram
SBClientPhishing.ClientSideDetection.AsyncCheckTriggerForceRequestResult.
This histogram will be useful to measure how often AsyncCheckTracker
notifies ClientSideDetectionHost and how often the request is enforced.

Bug: 342177553
Change-Id: I2a4f672a0db9f6b38ed861ab39e2b90765cfd951
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5586037


Reviewed-by: Seung Jae Lim <andysjlim@chromium.org>
Commit-Queue: Xinghui Lu <xinghuilu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1312161}