vue: improve accessibility for collapsible content

The following changes were made:

- aria-expanded: let's the user know if the content is displayed or not.
- aria-label: let's the user know what the content belongs to.

Change-Id: I6df9d42caded57fabfc760e2321d102a54ea8e87

Author: logan-connolly

Diff for: packages/cmk-frontend-vue/src/quick-setup/components/quick-setup/widgets/CollapsibleWidget.vue

@@ -39,7 +39,7 @@ const updateData = (id: string, value: Ref) => {
     :open="isOpen"
     @toggle-open="toggleOpen"
   />
-  <div v-show="isOpen">
+  <div v-show="isOpen" :aria-expanded="isOpen" :aria-label="props.title">
     <CompositeWidget
       :items="props.items"
       :data="props?.data || {}"