Avoid unnecessary stopTethering when startTethering fails

- If Wi-Fi tethering is enabled or enabling, avoid to startTethering again.

- If Wi-Fi tethering is disabled or disabling, avoid to stopTethering again.

- Add more logs to know which module stopped Tethering.

Bug: 230457055
Test: manual test
make RunSettingsRoboTests ROBOTEST_FILTER=WifiTetherSwitchBarControllerTest

Change-Id: I51d42ac0117d935ecaa9fa7312acc646b43d3593

src/com/android/settings/wifi/tether/TetherService.java

@@ -256,6 +256,7 @@ public class TetherService extends Service {
     }
 
     private void disableTethering(final int tetheringType) {
+        Log.w(TAG, "Disable tethering, type:" + tetheringType);
         final TetheringManager tm = (TetheringManager) getSystemService(Context.TETHERING_SERVICE);
         tm.stopTethering(tetheringType);
     }