Merge "Handle empty <cloud-backup> section in android:dataExtractionRules" into sc-dev am: b72bf2927e am: 7d77e932b6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15462078

Change-Id: I116e9ac5f19d016a0e0ea048b554acc9adbb0fd1