Move mac notification metrics to //chrome/services

This allows us to reuse the metrics collection code from both
//chrome/browser and //chrome/services and removes a duplication for
getting the style suffix. Made the "Banner" and "Alert" suffixes
consistent by deprecating other versions that haven't been launched yet.

Bug: None
Change-Id: I8dc825285fcbdece3e624e2b9fed81e5f38b0025
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3143999


Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Commit-Queue: Richard Knoll <knollr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#918759}