Wifi details - handle no profile owner

* If there is no profile owner, then do
  no call DPM method getProfileOwnerAsUser

Bug: 158284193
Test: manual testing
      make RunSettingsRoboTests -j ROBOTEST_FILTER=WifiDetailPreferenceController2Test
Change-Id: Ief1f0b3aa6805d69fc14da8f87a90c9b12bef8c6

src/com/android/settings/wifi/details2/WifiNetworkDetailsFragment2.java

@@ -142,9 +142,11 @@ public class WifiNetworkDetailsFragment2 extends DashboardFragment implements
                                 getContext().getSystemService(Context.USER_SERVICE);
                         final int profileOwnerUserId = Utils.getManagedProfileId(
                                 um, UserHandle.myUserId());
+                        if (profileOwnerUserId != UserHandle.USER_NULL) {
                             admin = new EnforcedAdmin(dpm.getProfileOwnerAsUser(profileOwnerUserId),
                                     null, UserHandle.of(profileOwnerUserId));
                         }
+                    }
                     RestrictedLockUtils.sendShowAdminSupportDetailsIntent(getContext(), admin);
                 } else {
                     showDialog(WIFI_DIALOG_ID);