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

api/apps/chunk_app.py

@@ -15,27 +15,25 @@
 #
 import datetime
 import json
+import re
 
+import xxhash
 from flask import request
-from flask_login import login_required, current_user
+from flask_login import current_user, login_required
 
-from rag.app.qa import rmPrefix, beAdoc
-from rag.app.tag import label_question
-from rag.nlp import search, rag_tokenizer
-from rag.prompts import keyword_extraction, cross_languages
-from rag.settings import PAGERANK_FLD
-from rag.utils import rmSpace
+from api import settings
 from api.db import LLMType, ParserType
+from api.db.services.document_service import DocumentService
 from api.db.services.knowledgebase_service import KnowledgebaseService
 from api.db.services.llm_service import LLMBundle
 from api.db.services.user_service import UserTenantService
-from api.utils.api_utils import server_error_response, get_data_error_result, validate_request
-from api.db.services.document_service import DocumentService
-from api import settings
-from api.utils.api_utils import get_json_result
-import xxhash
-import re
-
+from api.utils.api_utils import get_data_error_result, get_json_result, server_error_response, validate_request
+from rag.app.qa import beAdoc, rmPrefix
+from rag.app.tag import label_question
+from rag.nlp import rag_tokenizer, search
+from rag.prompts import cross_languages, keyword_extraction
+from rag.settings import PAGERANK_FLD
+from rag.utils import rmSpace
 
 
 @manager.route('/list', methods=['POST'])  # noqa: F821
@@ -129,9 +127,13 @@ def set():
     d["content_ltks"] = rag_tokenizer.tokenize(req["content_with_weight"])
     d["content_sm_ltks"] = rag_tokenizer.fine_grained_tokenize(d["content_ltks"])
     if "important_kwd" in req:
+        if not isinstance(req["important_kwd"], list):
+            return get_data_error_result(message="`important_kwd` should be a list")
         d["important_kwd"] = req["important_kwd"]
         d["important_tks"] = rag_tokenizer.tokenize(" ".join(req["important_kwd"]))
     if "question_kwd" in req:
+        if not isinstance(req["question_kwd"], list):
+            return get_data_error_result(message="`question_kwd` should be a list")
         d["question_kwd"] = req["question_kwd"]
         d["question_tks"] = rag_tokenizer.tokenize("\n".join(req["question_kwd"]))
     if "tag_kwd" in req:
@@ -235,6 +237,8 @@ def create():
     d["create_timestamp_flt"] = datetime.datetime.now().timestamp()
     if "tag_feas" in req:
         d["tag_feas"] = req["tag_feas"]
+    if "tag_feas" in req:
+        d["tag_feas"] = req["tag_feas"]
 
     try:
         e, doc = DocumentService.get_by_id(req["doc_id"])