Hide the new bouncer message views by default

They take up space in the layout even though we don't display any messages
The CL ag/23085660 that removes these views from layout when the flag is disabled couldn't be merged on time for the udc-dev cutoff

Fixes: 282890822
Test: verified manually, flashed the build, enabled layout bounds through dev options and don't see the new views on bouncer.
Change-Id: I90c3e325f01535fbc1edfe669d80541e901b6841