Update visibility to allow per-target Android.bp in AndroidX am: cf5ea95e16

Original change: https://android-review.googlesource.com/c/platform/external/kotlinx.metadata/+/2794375

Change-Id: I6e06c1a0002e41c0c8f75eb0abc092c051c17a79
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>