Non-associative arrays formatting is not consistent with associative arrays

Prettier 2.6.2

PHP Plugin 0.18.5

Input:

class Test
{
    protected $array1 = [
        'published', 'title', 'description', 'position', 'nid'];

    protected $array2 = [
        0=>'published', 'title', 'description', 'position', 'nid'];
}

Output:

class Test
{
    protected $array1 = ['published', 'title', 'description', 'position', 'nid'];

    protected $array2 = [
        0 => 'published',
        'title',
        'description',
        'position',
        'nid',
    ];
}

Expected behavior:

class Test
{
    protected $array1 = [
        'published',
        'title',
        'description',
        'position',
        'nid',
    ];

    protected $array2 = [
        0 => 'published',
        'title',
        'description',
        'position',
        'nid',
    ];
}

If we break any array (associative or not) into multiple lines it should format the array as multiple lines, as it does for associative arrays. Also, this comment states that the multi-line format should be preserved.

Reproduce the reported input with the Prettier PHP plugin versions listed in the issue and compare the output with the expected formatting. Start by tracing the plugin's array-formatting behavior, including the linked comment from issue 1401. Done means multiline non-associative arrays preserve their line breaks and match the shown expected output.