Use searchable="false" to suppress nonIndexables.

When possible, remove or simplify getNonIndexable() logic in fragments,
and use searchable="false" in xml to suppress index.

Change-Id: I5bdf5bc7d5494a64cdd9e230a51321a4b210af69
Fixes: 112608186
Test: robotest and manual search
diff --git a/src/com/android/settings/connecteddevice/AvailableMediaDeviceGroupController.java b/src/com/android/settings/connecteddevice/AvailableMediaDeviceGroupController.java
index 183ed3f..e0a7d27 100644
--- a/src/com/android/settings/connecteddevice/AvailableMediaDeviceGroupController.java
+++ b/src/com/android/settings/connecteddevice/AvailableMediaDeviceGroupController.java
@@ -95,7 +95,7 @@
     @Override
     public int getAvailabilityStatus() {
         return mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH)
-                ? AVAILABLE
+                ? AVAILABLE_UNSEARCHABLE
                 : UNSUPPORTED_ON_DEVICE;
     }