[DomCrawler] Allowed internal validation of ChoiceFormField to be disabled

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7672
| License       | MIT
| Doc PR        | Not yet

Hi,

Here is a quite basic attempt to be able to disable the internal validation of the ChoiceFormField. It's pretty basic. 
Feel free to tell me what you think guys. Maybe I should check the `validationDisabled` property at the beginning of the `containsOption()` method ?
I'll make the documentation PR as soon as the implementation will be validated.

Regards.