[sb] Don't pass in application context, use the root's instead

StatusBarRoot should just rely on its root, since it can be instantiated
for different windows

Test: none, changing the constructor
Bug: 364360986
Flag: com.android.systemui.status_bar_simple_fragment
Change-Id: I913ab832e8e7436b5d4831c82c9c5211802a01cd
1 file changed