Show mobile data slice in Search even no SIM card

- return slice like in airplan mode when mobile data disabled in the getSlice
  of the MobileDataSlice
- replace CONDITIONALLY_UNAVAILABLE by DISABLED_DEPENDENT_SETTING in the
  getAvailabilityStatus of the MobileDataPreferenceController
- remove the duplicated mobile data item by update data_usage_cellular.xml

Fixes: 130650621
Test: robotest
Change-Id: I42c0983c27d4edb17fcdce7ca386023911254d2d

src/com/android/settings/network/telephony/MobileDataPreferenceController.java

@@ -64,7 +64,7 @@ public class MobileDataPreferenceController extends TelephonyTogglePreferenceCon
     public int getAvailabilityStatus(int subId) {
         return subId != SubscriptionManager.INVALID_SUBSCRIPTION_ID
                 ? AVAILABLE
-                : CONDITIONALLY_UNAVAILABLE;
+                : DISABLED_DEPENDENT_SETTING;
     }
 
     @Override