[iOS] Password suggestion bubble eg test

Add earl grey test for password suggestion tip:
- Test that the tip shows when showing password suggestion for the first
  time.
- Test that the tip doesn't show when showing password suggestion for
  the second time.

Add feature engagement client config in app interface to enable feature
triggering.

Bug: 1315954
Change-Id: If387d414ac6b8640c65a2220098f0064b628b4d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3582585
Reviewed-by: edchin <edchin@google.com>
Commit-Queue: Louis Romero <lpromero@chromium.org>
Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1007674}
NOKEYCHECK=True
GitOrigin-RevId: 69cc37bd1ee2b5a9d6b4ac50c9774bc880694855
4 files changed