Don't add disabled menu items to selection menu

We currently add menu items to a list of items regardless of whether
they're enabled or not. We then do some processing across all items in
that list before finally building the final menu. When building the
menu, if the item isn't enabled, we don't add it. It's probably better
to just not add these menu items to the list in the first place.

This CL should not change menu behavior.

Change-Id: Iaee56bb04baf48a5f1eb962cc0edf75592113f13
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7036834
Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Alex Mitra <alexmitra@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1530744}