[Wi-Fi] Use startActivityForResult instead of startActivity to launch google help page

The startActivity API can not launch the help page.
Change to use startActivityForResult to launch.

Bug: 143784389
Test: Add learnMore_launchesHelp_shouldStartActivityForResult unit test to check if startActivityForResult be called.
Change-Id: Ia3ef82f94d4c8feb71131b44be26df74d6259805

src/com/android/settings/wifi/WifiScanningRequiredFragment.java

@@ -99,7 +99,7 @@ public class WifiScanningRequiredFragment extends InstrumentedDialogFragment imp
         Intent intent = getHelpIntent(getContext());
         if (intent != null) {
             try {
-                startActivity(intent);
+                getActivity().startActivityForResult(intent, 0);
             } catch (ActivityNotFoundException e) {
                 Log.e(TAG, "Activity was not found for intent, " + intent.toString());
             }