Let list_chat go without kb checking. (#5280)

### What problem does this PR solve?

#5278 

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

api/apps/sdk/chat.py

@@ -13,6 +13,8 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 #
+import logging
+
 from flask import request
 from api import settings
 from api.db import StatusEnum
@@ -318,7 +320,8 @@ def list_chat(tenant_id):
         for kb_id in res["kb_ids"]:
             kb = KnowledgebaseService.query(id=kb_id)
             if not kb:
-                return get_error_data_result(message=f"Don't exist the kb {kb_id}")
+                logging.WARN(f"Don't exist the kb {kb_id}")
+                continue
             kb_list.append(kb[0].to_json())
         del res["kb_ids"]
         res["datasets"] = kb_list

rag/raptor.py

@@ -71,7 +71,7 @@ class RecursiveAbstractiveProcessing4TreeOrganizedRetrieval:
         layers = [(0, len(chunks))]
         start, end = 0, len(chunks)
         if len(chunks) <= 1:
-            return
+            return []
         chunks = [(s, a) for s, a in chunks if s and len(a) > 0]
 
         def summarize(ck_idx, lock):