Remove navbar from CD

- Navbar is already removed for default display as it's functionality has moved to Taskbar.

Fix: 440416443
Flag: EXEMPT BUGFIX
Test: tested CUJs manually
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:f2e43550daa4ad5406f74bbe8e68864e7e3a2c4e
Merged-In: I4d6e584db596a6731d721176aabce22ae99f0a83
Change-Id: I4d6e584db596a6731d721176aabce22ae99f0a83