[BUG] checkboxPrompt duplicates values

Describe the bug When usingcheckboxPrompt with old values, the returned array has duplicate values.

To Reproduce

const values = await checkboxPrompt(['a', 'b', 'c', 'd'], ['a', 'b']);
console.log(values);

If you turn OFF a and b, and turn ON c, you get the correct output: ['c']. However, if you leave a or b on, they are duplicated in the result: ["a", "b", "a", "b", "c"]

[thorlucas]

Fairly simple fix, will close the issue once merged in

[chhoumann]

Thank you!