Add docUrl into metadata.

+                if (whiteLabelTheme.getDocUrl() == null) {
+                    whiteLabelTheme.setDocUrl(defaultTheme.getDocUrl());
+                    Metadata updatedMetadata = constructWhiteLabelThemeMetadata(whiteLabelTheme);
+                    MetadataManagementDAOFactory.beginTransaction();

         return metadata;
     }
 
+    private void updateWhiteLabelThemeWithDefaults(WhiteLabelTheme whiteLabelTheme, int tenantId)