Add an element identifier to the zoom page action

In order to make testing easier and easily use the kumbucha framework,
this CL adds an element identifier to the zoom page action action item.

Change-Id: I71b4ea1fe28a2c48d5832fbbc17f63997a9f460d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6333885
Reviewed-by: Dana Fried <dfried@chromium.org>
Reviewed-by: Kaan Alsan <alsan@chromium.org>
Commit-Queue: Daniel Soromou <koretadaniel@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1432109}