The model name to pass to tiktoken when using this class.
Tiktoken is used to count the number of tokens in documents to constrain them to be under a certain limit.
By default, when set to None, this will be the same as the embedding model
name. However, there are some cases where you may want to use this
Embedding class with a model name not supported by tiktoken. This can
include when using Azure embeddings or when using one of the many model
providers that expose an OpenAI-like API but with different models. In those
cases, in order to avoid erroring when tiktoken is called, you can specify a
model name to use here.
tiktoken_model_name: str | None = None