feat: Use Fluent SVG icons on the dashboard (#3482)

app/javascript/dashboard/components/Accordion/AccordionItem.vue

@@ -10,8 +10,8 @@
       <div class="button-icon--wrap">
         <slot name="button" />
         <div class="chevron-icon__wrap">
-          <i v-if="isOpen" class="ion-minus chevron-icon"></i>
-          <i v-else class="ion-plus chevron-icon"></i>
+          <fluent-icon v-if="isOpen" size="24" icon="subtract" type="solid" />
+          <fluent-icon v-else size="24" icon="add" type="solid" />
         </div>
       </div>
     </button>