Merge "libsnapshot: Fetch device size from header" into main am: 74287053 am: ea798470

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2974622



Change-Id: I50ddb0f2df300355471b0d49a56273950508bb9a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>