[VLM] Initialize video input support for InternVL models (#18499)

Signed-off-by: Isotr0py <2037008807@qq.com>
Co-authored-by: Cyrus Leung <cyrus.tl.leung@gmail.com>

vllm/entrypoints/chat_utils.py

@@ -556,6 +556,8 @@ class BaseMultiModalItemTracker(ABC, Generic[_T]):
                 return "(<audio>./</audio>)"
             raise TypeError(f"Unknown model type: {model_type}")
         elif modality == "video":
+            if model_type == "internvl_chat":
+                return "<video>"
             if model_type in ("qwen2_vl", "qwen2_5_vl"):
                 return "<|vision_start|><|video_pad|><|vision_end|>"
             if model_type == "qwen2_5_omni":