Test: Add list chunk checkpoint for the add chunk API (#6482)

### What problem does this PR solve?

Add list chunk checkpoint for the add chunk API

### Type of change

- [x] update test cases

sdk/python/test/test_http_api/common.py

@@ -191,8 +191,8 @@ def list_chunks(auth, dataset_id, document_id, params=None):
 
 
 def batch_add_chunks(auth, dataset_id, document_id, num):
-    ids = []
+    chunk_ids = []
     for i in range(num):
         res = add_chunk(auth, dataset_id, document_id, {"content": f"ragflow test {i}"})
-        ids.append(res["data"]["chunk"]["id"])
-    return ids
+        chunk_ids.append(res["data"]["chunk"]["id"])
+    return chunk_ids