Let the agent talk while there's pre-set param. (#4423)

### What problem does this PR solve?

#4385

### Type of change

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

api/apps/sdk/session.py

@@ -170,9 +170,9 @@ def agent_completions(tenant_id, agent_id):
         dsl = cvs[0].dsl
         if not isinstance(dsl, str):
             dsl = json.dumps(dsl)
-        canvas = Canvas(dsl, tenant_id)
-        if canvas.get_preset_param():
-            req["question"] = ""
+        #canvas = Canvas(dsl, tenant_id)
+        #if canvas.get_preset_param():
+        #    req["question"] = ""
         conv = API4ConversationService.query(id=req["session_id"], dialog_id=agent_id)
         if not conv:
             return get_error_data_result(f"You don't own the session {req['session_id']}")