[VLM] Remove image_input_type from VLM config (#5852)

Signed-off-by: Xiaowei Jiang <xwjiang2010@gmail.com>
Co-authored-by: Cyrus Leung <cyrus.tl.leung@gmail.com>
Co-authored-by: Roger Wang <ywang@roblox.com>

examples/openai_vision_api_client.py

@@ -3,7 +3,6 @@
 Launch the vLLM server with the following command:
 python -m vllm.entrypoints.openai.api_server \
     --model llava-hf/llava-1.5-7b-hf \
-    --image-input-type pixel_values \
     --image-token-id 32000 \
     --image-input-shape 1,3,336,336 \
     --image-feature-size 576 \