fix(cli): avoid success message after cancelled dataset deletion

[sridipbasu]

Summary

Fixes a bug in the dataset deletion CLI where a success message was printed even when the user cancelled the deletion confirmation.

Problem

When running:

kaggle datasets delete <owner>/<dataset>

and responding no to the confirmation prompt, the CLI printed:

Deletion cancelled
Dataset "<owner>/<dataset>" deleted successfully.

Although the deletion was cancelled, the success message was still displayed, resulting in misleading user feedback.

Root Cause

dataset_delete() returned after printing Deletion cancelled, but dataset_delete_cli() always printed the success message without checking whether the deletion had actually proceeded.

Solution

• Updated dataset_delete() to return whether the deletion was executed.
• Updated dataset_delete_cli() to print the success message only when the deletion completed successfully.

This change only affects the dataset deletion flow and does not modify the deletion logic itself.

Testing

Manual

• Created a temporary private dataset.
• Ran kaggle datasets delete <owner>/<dataset>.
• Answered no at the confirmation prompt.
• Verified that the dataset still existed.
• Confirmed that the success message is no longer printed after cancellation.

Automated

• Added unit tests covering:

  • cancellation path (success message is not printed)
  • successful deletion path (success message is printed)

• Ran the new dataset deletion tests successfully.

• Ran existing dataset-related unit tests to verify no regressions.

Before

Are you sure you want to delete the dataset: owner/dataset? [yes/no] no
Deletion cancelled
Dataset "owner/dataset" deleted successfully.

After

Are you sure you want to delete the dataset: owner/dataset? [yes/no] no
Deletion cancelled

Screenshot

A screenshot demonstrating the original incorrect behavior is attached for reference.

[sridipbasu]

Here's the Screenshot which is attached