Fix SettingsHelper by adding class to BySelector criteria of DND switch.

Bug: 38157405
Test: adb shell am instrument -w -e class com.android.androidbvt.SysSettingTests#testQuickSettingsChangeFromQuickSettingsPanel com.android.androidbvt/android.support.test.runner.AndroidJUnitRunner
Change-Id: I078dcd2d71d3c38641ed54e0381cfac23eabf0bc
diff --git a/libraries/system-helpers/settings-helper/src/android/system/helpers/SettingsHelper.java b/libraries/system-helpers/settings-helper/src/android/system/helpers/SettingsHelper.java
index f113a85..962e9e2 100644
--- a/libraries/system-helpers/settings-helper/src/android/system/helpers/SettingsHelper.java
+++ b/libraries/system-helpers/settings-helper/src/android/system/helpers/SettingsHelper.java
@@ -515,7 +515,7 @@
         try {
             int onSetting = Settings.Global.getInt(mResolver, ZEN_MODE);
             launchQuickSettingsAndWait();
-            mDevice.wait(Until.findObject(By.descContains(DND)),
+            mDevice.wait(Until.findObject(By.descContains(DND).clazz(Switch.class)),
                     TIMEOUT * 3).getChildren().get(0).click();
             Thread.sleep(TIMEOUT * 3);
             int changedSetting = Settings.Global.getInt(mResolver, ZEN_MODE);
@@ -527,7 +527,7 @@
             int setting = Settings.Global.getInt(mResolver, ZEN_MODE);
             if (setting > 0) {
                 launchQuickSettingsAndWait();
-                mDevice.wait(Until.findObject(By.descContains(DND)),
+                mDevice.wait(Until.findObject(By.descContains(DND).clazz(Switch.class)),
                         TIMEOUT * 3).getChildren().get(0).click();
                 Thread.sleep(TIMEOUT * 3);
             }