Nullcheck for StatusBarManagerInternal in InsetsPolicy

Wear does not support StatusBarManagerService

Bug: 158866039
Test: salmon boots successfully
Change-Id: I76a44c4cbc0f8eeeda6b9c35b2c29ce87f0db8de
Merged-In: I76a44c4cbc0f8eeeda6b9c35b2c29ce87f0db8de
(cherry picked from commit 3d40a967c3c111e205f577ab96daf7f2b696ee3e)
(cherry picked from commit 7f00ac7f25eb591dcd2dab851b60d4e598581ead)
2 files changed