Remove OmniboxShortcutsAndroid from field trial testing config

Change-Id: I3a9c18579472477dd5e81f2c90ee1b5a8bfa6aaa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5617317


Commit-Queue: Gang Wu <gangwu@chromium.org>
Reviewed-by: Tomasz Wiszkowski <ender@google.com>
Cr-Commit-Position: refs/heads/main@{#1313072}