[DOC] Update to 3.14 when possible

[ego-thales]

For now there are two problems with 3.14 and doc:

• RTD support Python 3.14 Support readthedocs/readthedocs.org#12523
• datasets support (changing underlying API). Infos:
  • Caching does not work when using python3.14 huggingface/datasets#7813
  • Caching does not work when using python3.14 uqfoundation/dill#725
  • discussino of fix: better args passthrough for _batch_setitems() huggingface/datasets#7817

As such, we disabled doc building from CI for 3.14.

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When fixed:

1. Update the version in RTD config file;
2. Enable doc building again, for 3.14 in CI;
3. Remove .. attention:: warning from the tutorial Visualizing & Evaluating OoD Detection algorithms.