[FEA]: Allow fully qualified reranking endpoint URLs

[nv-alaiacano]

Is this a new feature, an improvement, or a change to existing functionality?

Change

How would you describe the priority of this feature request

Currently preventing usage

Please provide a clear description of problem this feature solves

We have an internally hosted ranking endpoint that ends with /v1/rerank. The way that NRL parses the RERANKER_INVOKE_URL is with the following logic:

When ``rerank_invoke_url`` is set the actor/function calls a vLLM (>=0.14) or NIM
server that exposes the NIM ranking REST API. The helper accepts
either a fully qualified ``.../reranking`` URL or a base URL and appends
``/v1/ranking`` automatically::

This means that we end up in the following scenarios:

If RERANKER_INVOKE_URL=https://endpoint.com/v1/rerank, then the library calls https://endpoint.com/v1/rerank/v1/ranking

If RERANKER_INVOKE_URL=https://endpoint.com, then the library calls https://endpoint.com/v1/ranking

Describe the feature, and optionally a solution or implementation and any alternatives

It would be nice to be able to provide a custom URL that does not get manipulated by the library. We cannot currently use this feature of NRL because of this logic.

Additional context

No response