Refactor mm processors and Enable mixed modality processing (#7629)

Signed-off-by: Xinyuan Tong <justinning0323@outlook.com>

python/sglang/srt/multimodal/processors/kimi_vl.py

@@ -30,11 +30,6 @@ class KimiVLImageProcessor(SGLangBaseProcessor):
         *args,
         **kwargs,
     ):
-        if not image_data:
-            return None
-        if isinstance(image_data, str):
-            image_data = [image_data]
-
         base_output = self.load_mm_data(
             prompt=input_text,
             image_data=image_data,
@@ -44,10 +39,10 @@ class KimiVLImageProcessor(SGLangBaseProcessor):
             max_req_input_len=max_req_input_len,
         )
 
-        combined_mm_item, input_ids = self.process_and_combine_mm_data(base_output)
+        mm_items, input_ids = self.process_and_combine_mm_data(base_output)
 
         return {
             "input_ids": input_ids.tolist(),
-            "mm_items": [combined_mm_item] if combined_mm_item is not None else [],
+            "mm_items": mm_items,
             "im_token_id": self.IM_TOKEN_ID,
         }