Revert "Remove Permissions Hub."

This reverts commit 1e7c172ad5.

Bug: 132292477
Test: None.
Change-Id: Icae2cd4edbb22e2f3ea72e20f0ebd818f1ac6629

src/com/android/settings/privacy/PermissionBarChartPreferenceController.java

@@ -89,7 +89,10 @@ public class PermissionBarChartPreferenceController extends BasePreferenceContro
 
     @Override
     public int getAvailabilityStatus() {
-        return UNSUPPORTED_ON_DEVICE;
+        return Boolean.parseBoolean(
+                DeviceConfig.getProperty(DeviceConfig.NAMESPACE_PRIVACY,
+                        com.android.settings.Utils.PROPERTY_PERMISSIONS_HUB_ENABLED)) ?
+                AVAILABLE_UNSEARCHABLE : UNSUPPORTED_ON_DEVICE;
     }
 
     @Override