sysui: fix navbar button view orientation

Before navbar assumes rotation 0 means portrait and rotation 90
means landscape.  This is not necessarily true, in certain devices
the natural orientation (0) is landscape.  Here we removed that
assumption and make sure we use the right inflater at all times.

Bug: 32516898
Test: Locally on test device
Change-Id: I3db44dcb35d8511fb9d42b147b2bd137ff0750f7