Improve setAttribute to handle array list as value for translation

[alipadron]

This PR enhances the setAttribute method in the HasTranslations trait to handle array values for translatable attributes.

Motivation

Previously, setting an array value for a translatable attribute would result in unexpected behavior, treating array indexes as locale keys. For example:

$model->additional_info = ['Feature 1', 'Feature 2', 'Feature 3'];

Would store:

{
  "0": "Feature 1",
  "1": "Feature 2",
  "2": "Feature 3"
}

With this change, the array is now stored as a translation for the current locale:

{
  "en": ["Feature 1", "Feature 2", "Feature 3"]
}

Tests were added to verify the correct behavior of the setAttribute method with array values.

[freekmurze]

Thanks!