fix: Fix aria-controls attribute in fwb-sidebar-dropdown-item component and add documentation to assess ARIA allowed attribute issue (#255)

* Remove `aria-controls` attribute from `button` element

* Add `aria-controls` back in component

* Pass `dropdown-content` to `aria-controls`

src/components/FwbSidebar/FwbSidebarDropdownItem.vue

@@ -3,7 +3,7 @@
     <button
       type="button"
       class="flex items-center w-full p-2 text-base text-gray-900 transition duration-75 rounded-lg group hover:bg-gray-100 dark:text-white dark:hover:bg-gray-700 z-10"
-      aria-controls="dropdown-example"
+      aria-controls="dropdown-content"
       @click="toggleDropdown"
     >
       <slot name="icon">