anthropic[major]: support python 3.13 (#27916)

Last week Anthropic released version 0.39.0 of its python sdk, which
enabled support for Python 3.13. This release deleted a legacy
`client.count_tokens` method, which we currently access during init of
the `Anthropic` LLM. Anthropic has replaced this functionality with the
[client.beta.messages.count_tokens()
API](https://github.com/anthropics/anthropic-sdk-python/pull/726).

To enable support for `anthropic >= 0.39.0` and Python 3.13, here we
drop support for the legacy token counting method, and add support for
the new method via `ChatAnthropic.get_num_tokens_from_messages`.

To fully support the token counting API, we update the signature of
`get_num_tokens_from_message` to accept tools everywhere.

---------

Co-authored-by: Bagatur <22008038+baskaryan@users.noreply.github.com>

libs/partners/openai/langchain_openai/chat_models/base.py

@@ -886,8 +886,13 @@ class BaseChatOpenAI(BaseChatModel):
         _, encoding_model = self._get_encoding_model()
         return encoding_model.encode(text)
 
-    # TODO: Count bound tools as part of input.
-    def get_num_tokens_from_messages(self, messages: List[BaseMessage]) -> int:
+    def get_num_tokens_from_messages(
+        self,
+        messages: List[BaseMessage],
+        tools: Optional[
+            Sequence[Union[Dict[str, Any], Type, Callable, BaseTool]]
+        ] = None,
+    ) -> int:
         """Calculate num tokens for gpt-3.5-turbo and gpt-4 with tiktoken package.
 
         **Requirements**: You must have the ``pillow`` installed if you want to count
@@ -897,7 +902,18 @@ class BaseChatOpenAI(BaseChatModel):
         counting.
 
         OpenAI reference: https://github.com/openai/openai-cookbook/blob/
-        main/examples/How_to_format_inputs_to_ChatGPT_models.ipynb"""
+        main/examples/How_to_format_inputs_to_ChatGPT_models.ipynb
+
+        Args:
+            messages: The message inputs to tokenize.
+            tools: If provided, sequence of dict, BaseModel, function, or BaseTools
+                to be converted to tool schemas.
+        """
+        # TODO: Count bound tools as part of input.
+        if tools is not None:
+            warnings.warn(
+                "Counting tokens in tool schemas is not yet supported. Ignoring tools."
+            )
         if sys.version_info[1] <= 7:
             return super().get_num_tokens_from_messages(messages)
         model, encoding = self._get_encoding_model()