SettingsActivityIT: fix crash due to unclosed looper

Signed-off-by: Álvaro Brey <alvaro.brv@gmail.com>

src/androidTest/java/com/nextcloud/client/SettingsActivityIT.java

@@ -86,6 +86,7 @@ public class SettingsActivityIT extends AbstractIT {
         SettingsActivity sut = activityRule.launchActivity(null);
         sut.handleMnemonicRequest(intent);
 
+        Looper.myLooper().quitSafely();
         assertTrue(true); // if we reach this, everything is ok
     }
 }