Relation columns of *-to-one relationship not displayed correctly

[zachgarwood]

Description

When adding a Relation column of a *-to-one relationship (for example, BelongsTo or HasOne), the value is not shown. Instead, a series of commas is displayed.

Steps to reproduce

Create a controller for a model with a BelongsTo relationship. In the additionalIndexTableColumns() method, add a Relation column for the related model's field:

use A17\Twill\Services\Listings\Columns\Relation;
use A17\Twill\Services\Listings\TableColumns;

protected function additionalIndexTableColumns(): TableColumns
{
        $columns = TableColumns::make();
        $columns->add(
            Relation::make()
                ->field('title')
                ->title('Grouping')
                ->relation('grouping')
        );
        

        return $columns;
}

Expected result

I expect it to display the value of the field of the related model.

Actual result

A series of commas is displayed instead. See the "Grouping" column in this image for an example:

Versions

Twill version: 3.4.1
Laravel version: v10.19.0
PHP version: 8.31

[zachgarwood]

It looks like this is a duplicate of #2682