Add screen timeout destination to settings

When an intent with action android.settings.SCREEN_TIMEOUT_SETTINGS is
launched, ScreenTimeoutSettings should be shown in settings

Bug: 293813663
Test: manual and local build verify
Change-Id: I1340cd3c233aa5d36f45b53b0fd2b6924f3a1d75
diff --git a/src/com/android/settings/Settings.java b/src/com/android/settings/Settings.java
index 68ae0ae..86baba4 100644
--- a/src/com/android/settings/Settings.java
+++ b/src/com/android/settings/Settings.java
@@ -478,4 +478,6 @@
     public static class OneHandedSettingsActivity extends SettingsActivity { /* empty */ }
 
     public static class PreviouslyConnectedDeviceActivity extends SettingsActivity { /* empty */ }
+
+    public static class ScreenTimeoutActivity extends SettingsActivity { /* empty */ }
 }