Delete NPVC.onStatusBarWindowStateChanged

This code originated in 2013 to fix b/8682123. It's use case is now
covered by other things like ActivityStarter, so this code is no longer
necessary and causing problems for other components.

Fixes: 351838854
Flag: EXEMPT bug fix
Test: Opened the shade, started camera app with power button, revealed status bar
Change-Id: Ia7cb5c6eaa5499d88966b4d344a151fe5c234dce