MNT replace deprecated _validate_data with validate_data (closes #290)

[floriankozikowski]

Context of the PR

fixes issue #290

Contributions of the PR

changes _validate_data with validate_data
with sklearn.utils.validation import validate_data

Checks before merging PR

n/a

• added documentation for any new feature
• added unit tests
• edited the what's new (if applicable)

[mathurinm]

@floriankozikowski thanks for the PR, we have updated main to fix other failing tests, so you need to git pull upstream main to integrate these changes, then git push for the UT to run with the correct changes

[mathurinm]

@floriankozikowski I guess in the requirements (that are inside pyproject.toml) we need to require sklearn >= 1.6 now since validate_data did not exist before ?

See https://scikit-learn.org/stable/modules/generated/sklearn.utils.validation.validate_data.html