Do not block broadcast on handler processing

Instead of blocking the broadcast until onReceive returns on the
handler, only post in onReceive.

This should make no difference for the only user, the
mCarrierConfigChange listener in Tethering.java, as the callback still
runs on the handler.

Bug: 349919195
Test: atest
Change-Id: Ie8ce7afbe905b4c6972b3aabda2d7792c96eda6c
2 files changed