[Wi-Fi] Fix a unit test fail in WifiMasterSwitchPreferenceControllerTest

In ag/10785119, WifiStatusTracker#setListening calls
ConnectivityManager#unregisterNetworkCallback twice.
Modify the fail test to match it.

Bug: 151696220
Test: make RunSettingsRoboTests ROBOTEST_FILTER=WifiMasterSwitchPreferenceControllerTest
Change-Id: Idd9917ce204e2abbc4bfbf760222191adadf4afa