Do not duplicate tool call parameters if they are identical

[michalwarda]

When using streaming with tools in ChatGoogleAI I've noticed that the merge method in tool_calls duplicated the name of the function.

Because of that the tool calls were not working. For some reason ChatGoogleAI sends the same message delta with tools twice.

Below you can see that the name of the function was being duplicated: image_1__generate_image converted into image_1__generate_imageimage_1__generate_image.

primary: %LangChain.MessageDelta{
  content: nil,
  status: :complete,
  index: 0,
  role: :assistant,
  tool_calls: [
    %LangChain.Message.ToolCall{
      status: :incomplete,
      type: :function,
      call_id: "call-image_1__generate_image",
      name: "image_1__generate_image",
      arguments: %{"prompt" => "a dog"},
      index: nil
    }
  ]
}
delta call: %LangChain.Message.ToolCall{
  status: :incomplete,
  type: :function,
  call_id: "call-image_1__generate_image",
  name: "image_1__generate_image",
  arguments: %{"prompt" => "a dog"},
  index: nil
}
merged call: %LangChain.Message.ToolCall{
  status: :incomplete,
  type: :function,
  call_id: "call-image_1__generate_image",
  name: "image_1__generate_imageimage_1__generate_image",
  arguments: %{"prompt" => "a dog"},
  index: nil
}

I've introduced a fix that makes same messagedelta with tool call not duplicate

[brainlid]

Yeesh! Thanks @michalwarda for figuring that out.

❤️💛💙💜