Refactor error_response function for improved argument handling

- Enhanced the `error_response` function to support backward compatibility by normalizing arguments when positional arguments are misused.
- Updated various views to pass `None` for the `errors` parameter in `error_response` calls, ensuring consistent response formatting.
- Adjusted logging in `ContentSyncService` and `WordPressClient` to use debug level for expected 401 errors, improving log clarity.
- Removed deprecated fields from serializers and views, streamlining content management processes.

frontend/src/config/pages/tasks.config.tsx

@@ -259,7 +259,7 @@ export const createTasksPageConfig = (
         ...wordCountColumn,
         sortable: true,
         sortField: 'word_count',
-        render: (value: number) => value.toLocaleString(),
+        render: (value: number | null | undefined) => (value != null ? value.toLocaleString() : '-'),
       },
       {
         ...createdColumn,