Background location permission should elevate the standby bucket to FREQUENT

Uid that has permission ACCESS_BACKGROUND_LOCATION will have at least
STANDBY_BUCKET_FREQUENT.

Bug: 183034945
Test: atest frameworks/base/services/tests/servicestests/src/com/android/server/usage/AppStandbyControllerTests.java#testBackgroundLocationBucket
Change-Id: I83caceb464faeda242e06e4a46faf7749b1bcf65