Sklearn 1.6 support

[Alexsandruss]

Description

Changes:

• Set SCIPY_ARRAY_API to 1 which is required for sklearn>=1.6 if array-api-compat is installed in:
  • sklearnex config context
  • testing script
• Update input validation in GBT and AdaBoost daal4py estimators
• Update parameters validation logic for pairwise_distances

---

PR should start as a draft, then move to ready for review state after CI is passed and all applicable checkboxes are closed.
This approach ensures that reviewers don't spend extra time asking for regular requirements.

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Checklist to comply with before moving PR from draft:

PR completeness and readability

• I have reviewed my changes thoroughly before submitting this pull request.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation to reflect the changes or created a separate PR with update and provided its number in the description, if necessary.
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Testing

• I have run it locally and tested the changes extensively.
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• I have extended testing suite if new functionality was introduced in this PR.

Performance

N/A

[Alexsandruss]

/intelci: run

[Alexsandruss]

/intelci: run

[Alexsandruss]

/intelci: run

[Alexsandruss]

/intelci: run

[Alexsandruss]

/intelci: run

[Alexsandruss]

/intelci: run

[icfaust]

Overall pretty good. @Alexsandruss are we going to do anything to control the sklearn version in conda-recipe to prevent CI failures, or was that bug a feature?

[Alexsandruss]

/intelci: run

[icfaust]

Merge on green CI, we will need to also make tickets to upgrade private CI and update the public README.md about support.

[Alexsandruss]

/intelci: run

[ethanglaser]

I guess this should also be updated: https://github.com/uxlfoundation/scikit-learn-intelex/blob/main/doc/sources/quick-start.rst?plain=1#L377-L382

[ethanglaser]

LGTM. Is the SCIPY_ARRAY_API something we should eventually be supporting internally? Would a follow-up ticket make sense here?

[ethanglaser]

Merge on green CI, we will need to also make tickets to upgrade private CI and update the public README.md about support.

I have added a ticket for private CI

[Alexsandruss]

I guess this should also be updated: https://github.com/uxlfoundation/scikit-learn-intelex/blob/main/doc/sources/quick-start.rst?plain=1#L377-L382

Separate PR with update of supported versions and others docs would be better.