[iOS] Remove ui_internal target

The target has been split in multiple targets. It is currently empty.
This CL removes it.

Bug: 944008
Change-Id: I0b7d9147d229408cd4e9cac93a64a36b6bffd7bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1534163
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#643395}
16 files changed