Show the banner if there's a new message (#1045)

Author: LucaRed

stubs/inertia/resources/js/Jetstream/Banner.vue

@@ -1,10 +1,14 @@
 <script setup>
-import { computed, ref } from 'vue';
+import { computed, ref, watch } from 'vue';
 import { usePage } from '@inertiajs/inertia-vue3';
 
 const show = ref(true);
 const style = computed(() => usePage().props.value.jetstream.flash?.bannerStyle || 'success');
 const message = computed(() => usePage().props.value.jetstream.flash?.banner || '');
+
+watch(message, async () => {
+  show.value = true;
+});
 </script>
 
 <template>