[5.7] Call proper validator interface method on a form request

[X-Coder264]

As #25152 which contained two changes unfortunately didn't get merged I created this PR which contains only the first change of that PR.

1. In ValidatesWhenResolvedTrait the passes method was called on a \Illuminate\Contracts\Validation\Validator instance even though the passes method doesn't exist on the interface. This was adjusted to call the fails method which is present on the interface and thus I avoided making a breaking change (adding the passes method to the interface).