Added authenticatable model class in config file

[PetroZaburko]

In case if you use observer on model FilamentComment to send email notification with queue like this:

class CommentObserver
{
    public function created(FilamentComment $comment): void
    {
        if ($manager = $comment->user->manager) {
            Mail::to($manager)->queue(new CommentMail($comment));
        }
    }
}

you will catch an error:
local.ERROR: Cannot use "::class" on value of type null {"exception":"[object] (TypeError(code: 0): Cannot use \"::class\" on value of type null at .../vendor/parallax/filament-comments/src/Models/FilamentComment.php:28).

So, maybe it's better to set up variable $authenticatable from config file.

[luke-parallax]

That's great thank you @PetroZaburko! This will be included in the next release.