Merge "Add API to get remaining lifetime as a percentage." into main am: f75d8fc2

Original change: https://android-review.googlesource.com/c/platform/system/vold/+/2940229



Change-Id: Ifbecbd4442b970b87605b6c223e89efd11f5bcba
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>