fix: old version logprobs to true

src/addImage.tsx

@@ -246,6 +246,7 @@ export function AddImage({
                         token: 65,
                         example: false,
                         audio: null,
+                        logprobs: null,
                       });
 
                       setChatStore({ ...chatStore });

src/app.tsx

@@ -217,6 +217,7 @@ export function App() {
         message.token = calculate_token_length(message.content);
     }
     if (ret.cost === undefined) ret.cost = 0;
+    if (ret.logprobs === undefined) ret.logprobs = true;
     return ret;
   };