Merge "Update the text of background app battery usage notification." into tm-dev am: 885af3d5

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17697827



Change-Id: I199e56cf08e4d1acdd3bf6d105a47a5779d7bde5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>