Merge "[Thread] Make ThreadConfiguraiton a system API" into main am: 1dbacf6b64

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3140397

Change-Id: If172d8c82d026b3f56785739d345f0eac10ff78e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>