Update PromptFormat.java

Author: kirklandsign

examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/PromptFormat.java

@@ -80,7 +80,7 @@ public static String getStopToken(ModelType modelType) {
       case LLAVA_1_5:
         return "</s>";
       case QWEN_3:
-        return "<|im_end|>";
+        return "<|endoftext|>";
       default:
         return "";
     }