Change include_descriptors default to None and better handling of label names

[maclandrol]

Changelogs

• include_descriptors is not disabled by default and label_names does not need to be provided to get eval loss.

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Checklist:

• Add tests to cover the fixed bug(s) or the new introduced feature(s) (if appropriate).
• Update the API documentation if a new function is added, or an existing one is deleted. Eventually consider making a new tutorial for new features.
• Write concise and explanatory changelogs below.
• If possible, assign one of the following labels to the PR: feature, fix or test (or ask a maintainer to do it for you).

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See #49

[maclandrol]

ping @Anri-Lombard

[Anri-Lombard]

Thank you for the quick move @maclandrol! I briefly made include_descriptors False and it still did not record the validation loss, but I see you made a few logic changes that I'll need to download locally and run; I'll do this in 60-ish minutes 👍

[Anri-Lombard]

@maclandrol I can confirm this worked! 🙂