Listen for CONNECTIVITY_ACTION broadcasts in WifiSetupActivity

In some cases, NETWORK_STATE_CHANGED_ACTION broadcasts are sent before
the current network state has been updated in ConnectivityService. Listening
for CONNECTIVITY_ACTION broadcasts as well ensures that we properly catch
new connections and auto-advance appropriately.

Bug: 18503725
Change-Id: Ia414d57d196d09171342fb3ae93c7e826cb1a1aa