Add a label to the batch actions form to make it a landmark

For a form to be a landmark and be announced by screen readers, it needs
to have an associated accessible name [1].

> Using the <form> element will automatically communicate a section of
> content as a form landmark, if it is provided an accessible name.

[1] - https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles/form_role

Closes #5274

admin/app/components/solidus_admin/ui/table/component.html.erb

@@ -88,7 +88,7 @@
   </div>
 
   <div class="<%= toolbar_classes %>" data-<%= stimulus_id %>-target="batchToolbar">
-    <%= form_tag '', id: batch_actions_form_id %>
+    <%= form_tag '', id: batch_actions_form_id, "aria-label" => t(".batch_actions") %>
     <% @batch_actions.each do |batch_action| %>
       <%= render_batch_action_button(batch_action) %>
     <% end %>

admin/app/components/solidus_admin/ui/table/component.yml

@@ -6,5 +6,6 @@ en:
   filter: 'Filter'
   search_placeholder: 'Search all %{resources}'
   refine_search: 'Refine Search'
+  batch_actions: Batch actions
   clear: Clear
   cancel: Cancel