ELA-1432: accessibility, set aria-hidden and focusable=false on icon

Apply attributes when an icon is defined, no visible label is present,
and an aria-label is provided.

Author: libetho

templates/patterns/button/pattern-button.html.twig

@@ -4,9 +4,19 @@
  * Button pattern.
  */
 #}
-{% if icon %}
-  {% set icon_data = icon is iterable ? icon : { name: icon } %}
-  {% set _icon = { path: bcl_icon_path }|merge(icon_data) %}
+{%  if icon %}
+  {% set _icon = {
+    path: bcl_icon_path,
+    name: icon,
+    attributes: create_attribute()
+  } %}
+  {% if label is empty and attributes['aria-label'] is not empty %}
+    {% set _icon = _icon|merge({
+      attributes: _icon.attributes
+        .setAttribute('aria-hidden', 'true')
+        .setAttribute('focusable', 'false')
+    }) %}
+  {% endif %}
 {% endif %}
 {% include '@oe-bcl/button' with {
   'label': label,