Fixes the connection listener wrong thread crash for overview proxy

Sending connection callbacks from binder thread crashes any layouts
called from the listener. Use the original handler to post connections
to fix this crash.

Bug: 67957962
Test: manual, reinstall launcher to re-establish the connection
Change-Id: I958d86346c41cbf1e9a0dc8bdeae957ec64f8a55
1 file changed