Use Context in Notification PermissionHelper

The context.checkPermission method has some logic not included in the
current PermissionManagerServiceInternal.checkUidPermission, such as
short-circuiting checks for system UID.

Test: atest PermissionHelperTest
Bug: 275709830
Change-Id: If6ac68a243e1222cb91985ef2055b4150c973d3f
3 files changed