Add a handler thread check to all public methods am: d5b24b4855 am: 0d95465152 am: 1c5f297a39 am: 682e392d20

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2593665

Change-Id: I4b17a78623969bd3d37e03ed5ce8b6780a2ed293
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>