[ValidateMixin] fire validations on readOnly fields

[geniuspacs]

Expected behavior

As is specified on W3C, readOnly fields must not be validated

https://www.w3.org/TR/2010/WD-html5-20100624/common-input-element-attributes.html#:~:text=The%20readonly%20attribute%20is%20a,is%20barred%20from%20constraint%20validation.

https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Attributes/readonly#constraint_validation

Actual Behavior

When we use for example telephone-input with