Missing button label and decorative image present

[cyberbaloo]

Bug Report

Problematic behavior
The accessible name of the dropdown list opening button is the icon font name. This arrow_drop_down icon is decorative and should not be rendered.

Possible Solution
Before

<button class="c__button c__button--neutral c__button--neutral--tertiary c__button--nano c__select__inner__actions__open c__button--icon-only" type="button"><span class="c__button__icon"><span class="material-icons">arrow_drop_down</span></span></button>

After

<button class="c__button ... c__button--icon-only" type="button"
aria-label="Ouvrir la liste des formats"(…) <span class="c__button__icon">
<span class="material-icons" aria-hidden="true">arrow_drop_down</span>
</span></button>

Critères RGAA
Critère 7.1 : Chaque script est-il, si nécessaire, compatible avec les technologies d'assistance ?

Impact
The user hears "arrow_drop_down", the text corresponds to the icon name and does not describe the action they are going to perform.

[Ovgodd]

PR : suitenumerique/cunningham#379