Test: Add tests for chunk API endpoints (#8616)

### What problem does this PR solve?

- Add comprehensive test suite for chunk operations including:
  - Test files for create, list, retrieve, update, and delete chunks
  - Authorization tests
  - Batch operations tests
- Update test configurations and common utilities
- Validate `important_kwd` and `question_kwd` fields are lists in
chunk_app.py
- Reorganize imports and clean up duplicate code

### Type of change

- [x] Add test cases

test/testcases/test_http_api/conftest.py

@@ -13,7 +13,6 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 #
-
 from time import sleep
 
 import pytest