fix: use correct prompt template in agg_qwen.yaml (#2909)

Signed-off-by: GuanLuo <41310872+GuanLuo@users.noreply.github.com>

examples/multimodal/deploy/agg_qwen.yaml

@@ -65,4 +65,4 @@ spec:
             - /bin/sh
             - -c
           args:
-            - 'python3 components/processor.py --model Qwen/Qwen2.5-VL-7B-Instruct --prompt-template "USER: <image>\n<prompt> ASSISTANT:"'
+            - 'python3 components/processor.py --model Qwen/Qwen2.5-VL-7B-Instruct --prompt-template "<|im_start|>system\nYou are a helpful assistant.<|im_end|>\n<|im_start|>user\n<|vision_start|><|image_pad|><|vision_end|><prompt><|im_end|>\n<|im_start|>assistant\n"'