Merge "Lock down String8|16.string() usage" into main am: f9cae2c965 am: 998b5a1313 am: a36c7fe8f5 am: b3ab330a27

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2706173

Change-Id: I5d8943cfb3fc7ec506677798f80c0fea798564a7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>