Fix: self-deployed LLM error, (#9217)

### What problem does this PR solve?

Close #9197
Close #9145

### Type of change

- [x] Refactoring
- [x] Bug fixing.

api/db/services/canvas_service.py

@@ -173,7 +173,8 @@ def completion(tenant_id, agent_id, session_id=None, **kwargs):
     conv.message.append({"role": "assistant", "content": txt, "created_at": time.time(), "id": message_id})
     conv.reference = canvas.get_reference()
     conv.errors = canvas.error
-    API4ConversationService.append_message(conv.id, conv.to_dict())
+    conv = conv.to_dict()
+    API4ConversationService.append_message(conv["id"], conv)
 
 
 def completionOpenAI(tenant_id, agent_id, question, session_id=None, stream=True, **kwargs):

api/db/services/llm_service.py

@@ -225,6 +225,9 @@ class TenantLLMService(CommonService):
                 if llm_id == llm["llm_name"]:
                     return llm["model_type"].split(",")[-1]
 
+        for llm in LLMService.query(llm_name=llm_id):
+            return llm.model_type
+
 
 class LLMBundle:
     def __init__(self, tenant_id, llm_type, llm_name=None, lang="Chinese", **kwargs):