feat: add rank_fields to rerank v3

[mahjongmen]

No description provided.

[harry-cohere]

Thanks for the contribution! We'll need to update the minimum SDK version to 5.2.5, which is blocked currently. We'll work on resolving this though.

[harry-cohere]

As above - I'll get back to you!

[btiernay]

This seems to have broken compatibility with the cohere.BedrockClientV2 client which does not support the rank_fields option. To fix this, I've have to patch using:

    # HACK: Override the `rerank` method to remove any unsupported parameters in this version of LangChain.
    cohere.BedrockClientV2.rerank = (lambda original:
                                     lambda self, *args, **kwargs: original(
                                         self, *args,
                                         **{k: v for k, v in kwargs.items() if
                                            k in inspect.signature(original).parameters}
                                     )
                                     )(cohere.BedrockClientV2.rerank)

cohere.BedrockClientV2 is required in my case because its the only client that supports rerank