In date rules use `format` property for format date in error message when don't set other format properties

For example:

```php
new Date(
 format: 'php:d.m.Y',
 min: '19.11.2013',
 max: '31.12.2099',
 skipOnEmpty: true,
),
```

In this case I expect that in error message date will be formatted as `php:d.m.Y`.