Merge "Remove usage of base/string/* in libfs_avb" into main am: 752112003d am: 5a8a1d704a

Original change: https://android-review.googlesource.com/c/platform/system/core/+/3265051

Change-Id: Ie4cab2eda0999e8b8c4c7550aaff9f480337d557
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>