[Thread] rename requestThreadNetwork to registerThreadNetworkCallback am: 0ffdc107e7

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3265031

Change-Id: I7b848d40d07ed33c8ba08a249ff52dd794044ac5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>