[iOS] Establish GLIC Flow For FRE/PageActionMenu GLIC Button

GLICCoordinator starts from one of two entry points: 1) The promo
manager triggers the GLIC Promo 2) The PageActionMenu GLIC Button entry
point

This CL creates the following behavior, if we enter from:
- entry point 1, the promo view is shown.
- entry point 2, the consent view is shown if a user hasn't granted
consent
- entry point 2 and consent has been granted, `GLICOverlay` will be
displayed

Additionally, this CL:
- Enables the feature engagement flag so GLIC components can properly
use the Feature Engagement Tracker(FET)
- Doesn't show the GLIC promo if the promo was shown already
- Notifies FET to update the GLIC promo pref value

For the first entry point, the old logic in GLICNavigationController
would open GLICPromo. With this CL, GLICCoordinator and
GLICNavigationController will have an added property to check if we
should skip over the GLIC Promo and only show GLIC Consent. This use
case is important for the second entry point since the promo isn't shown
but the consent view is.

Also side note, the GLIC promo currently doesn't have any other triggers
besides showing as a promo which makes logic simpler as we only need to
check

Bug: 419064727
Change-Id: Ia0a9c2dce196e28aa48c18caaf18e4bd325f9415
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6580382
Commit-Queue: Joemer Ramos <joemerramos@google.com>
Reviewed-by: Robbie Gibson <rkgibson@google.com>
Cr-Commit-Position: refs/heads/main@{#1466707}