[Extensions c2s] Change context menu icon when extension is pinned

Change context menu icon to pin icon only for button normal state when
the action is pinned in the toolbar. All other button states should
maintain the same icon, as well as the callback.

Screencast: https://drive.google.com/file/d/1iPi3f3UCTqELNlMJBZcszWcIHW4ccOa5/view?usp=sharing

Bug: 1390952
Change-Id: Ifb56a7af75f0ff4d0565c4b70ddca069318e61e6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4366864
Commit-Queue: Emilia Paz <emiliapaz@chromium.org>
Reviewed-by: Elaine Chien <elainechien@chromium.org>
Reviewed-by: Devlin Cronin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1128886}