feat: Add classifier deletion functionality

- Added `delete_classifier` function to delete a classifier by ID.
- Added corresponding unit tests for the new function.
- Updated the client example to demonstrate classifier deletion.
- Renamed `jina_client_test.v` to `api_test.v` for better organization.
- Renamed `model_embed.v` to `embeddings_api.v` for better organization.
- Refactored the embedding API to use enums for task and truncate types,
  and added error handling for invalid inputs.

examples/clients/jina.vsh

@@ -56,5 +56,12 @@ classify_result := jina_client.classify(
 
 println('Classification result: ${classify_result}')
 
+// List classifiers
 classifiers := jina_client.list_classifiers() or { panic('Error fetching classifiers: ${err}') }
 println('Classifiers: ${classifiers}')
+
+// Delete classifier
+delete_result := jina_client.delete_classifier(classifier_id: classifiers[0].classifier_id) or {
+	panic('Error deleting classifier: ${err}')
+}
+println('Delete result: ${delete_result}')