Remove Toggle System UI options from Support7Demos

As system ui visibility can not be reliably controlled
at the moment for <v11. Remove this from the demo.

Bug: 8910792.

Change-Id: Id55f8ae57c0961130c2ad2ab7a5b97cc43e36883
Signed-off-by: Chris Banes <chrisbanes@google.com>
3 files changed