Fix checkbox / switch fields invalid state

[ldaspt]

In the custom form theme block checkbox_radio_label, the field validity is incorrectly determined using form.parent.vars.valid. This checks the validity of the entire parent form, not the individual field.

Fix #31

❌ Current behavior

{% if checked and form.parent.vars.valid == false %}
    {% set valid = false %}
{% endif %}

Even if the current field has no validation error, it is marked as invalid if any other field in the parent form is invalid.

✅ Expected behavior

The validity check should be scoped to the current field only.

🛠️ Impact

This causes incorrect error styling on checkbox or radio labels, even when they are valid, as soon as any unrelated form field fails validation.

[j0r1s]

just as a follow up, I have overridden the checkbox_radio_label and switch_label blocks with your fix on one of my project and this seems to fix the issue well !

thanks a lot