Add accessible fieldset for checkboxes and radio buttons
As per https://www.w3.org/WAI/tutorials/forms/grouping , grouped form controls like radio buttons/checkboxes must be enclosed in
<fieldset> and the
<legend> element act as a header to identify the group of elements. Currently, when we review such block with WAVE accessibility tool, it complains about:
- Enclose the checkbox/radio button block in a fieldset
- Add a special class to that fieldset say
crm-sr-fieldsetwhich hides it in front-end forms (public and backoffice forms)
- Use label of checkbox/radio buttons as its legend header.