Merge "aconfig_storage_read_api: make map_file function public." into main am: adba533072

Original change: https://android-review.googlesource.com/c/platform/build/+/3312556

Change-Id: I888e5e7de3d0861366c1053ce8e9d44a2a997246
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>