[Output Swithcer] Add groupable routes when build list

This change should only take effect when there's any route which is
groupable but not transferrable.

Bug: 223614810
Test: Verified on device
Change-Id: I39a1047ec7e607835b8998672b94f39f9c2c30b7

packages/SettingsLib/src/com/android/settingslib/media/InfoMediaManager.java

@@ -465,6 +465,7 @@ public class InfoMediaManager extends MediaManager {
         RoutingSessionInfo routingSessionInfo = getRoutingSessionInfo(packageName);
         if (routingSessionInfo != null) {
             infos.addAll(mRouterManager.getSelectedRoutes(routingSessionInfo));
+            infos.addAll(mRouterManager.getSelectableRoutes(routingSessionInfo));
         }
         final List<MediaRoute2Info> transferableRoutes =
                 mRouterManager.getTransferableRoutes(packageName);