[Bugfix] Remove CustomChatCompletionContentPartParam multimodal input type (#10054)

Signed-off-by: Zifei Tong <zifeitong@gmail.com>

vllm/entrypoints/chat_utils.py

@@ -22,7 +22,6 @@ from openai.types.chat import (ChatCompletionMessageToolCallParam,
                                ChatCompletionToolMessageParam)
 # yapf: enable
 # pydantic needs the TypedDict from typing_extensions
-from pydantic import ConfigDict
 from transformers import PreTrainedTokenizer, PreTrainedTokenizerFast
 from typing_extensions import Required, TypeAlias, TypedDict
 
@@ -52,13 +51,6 @@ class ChatCompletionContentPartAudioParam(TypedDict, total=False):
     """The type of the content part."""
 
 
-class CustomChatCompletionContentPartParam(TypedDict, total=False):
-    __pydantic_config__ = ConfigDict(extra="allow")  # type: ignore
-
-    type: Required[str]
-    """The type of the content part."""
-
-
 class CustomChatCompletionContentSimpleImageParam(TypedDict, total=False):
     """A simpler version of the param that only accepts a plain image_url.
     This is supported by OpenAI API, although it is not documented.
@@ -85,7 +77,6 @@ class CustomChatCompletionContentSimpleAudioParam(TypedDict, total=False):
 ChatCompletionContentPartParam: TypeAlias = Union[
     OpenAIChatCompletionContentPartParam, ChatCompletionContentPartAudioParam,
     ChatCompletionContentPartRefusalParam,
-    CustomChatCompletionContentPartParam,
     CustomChatCompletionContentSimpleImageParam,
     CustomChatCompletionContentSimpleAudioParam, str]