Add ChromeFromGwsAbandonedPageLoadMetricsObserver

This CL adds `ChromeFromGwsAbandonedPageLoadMetricsObserver` to measure
the abandoned navigations which happened from GWS. It adds the
AbandonedReason metrics to the obsersver.

UKM doc (internal): https://docs.google.com/document/d/1EqFy9moxI2evwPzsz2QVy14fl3IUA9kK0derSkhOocE/edit?resourcekey=0--uRO-PqdAxK9jjwYypUmLQ&tab=t.0#heading=h.k5jx6iluw4yt

Bug: 390216631
Change-Id: I322516935f4d6e5833337868d8740aa27ccbd278
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6176641
Reviewed-by: Shunya Shishido <sisidovski@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Keita Suzuki <suzukikeita@chromium.org>
Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1426596}