➕Add warnings ⚠️ for inproper task setting in config files.

[samet-akcay]

Description

• This PR adds checks to see if the task is properly assigned in folder dataset.

• Fixes Test anomalib with unsupervised dataset #273

Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist

• My code follows the pre-commit style and check guidelines of this project.
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes

[ashwinvaidya17]

I think this will also address the comment on the issue about classification task producing only binary predictions rather than anomaly masks.

[djdameln]

I guess the task type parameter really is redundant for the folder dataset. Especially now that performance metrics are configurable. The user can now choose between classification and segmentation evaluation in 3 ways: task_type parameter, mask_path parameter and metrics.pixel parameter. In understand why this confuses the users, and I feel we need a better design for this. But let's merge this PR as a quick fix and create a better design separately.

[samet-akcay]

I agree it's not so intuitive. We need to make it simpler.