Actually use 'loading' in the Folder creation modal

src/components/Navigation/AddFolderModal.vue

@@ -92,6 +92,7 @@ export default {
     ...mapMutations('notifications', ['notify']),
     async addFolder () {
       if (this.loading || !this.canWrite(this.corpus) || !this.typeSlug || !this.name) return
+      this.loading = true
       try {
         const folder = await this.$store.dispatch('elements/create', {
           corpus: this.corpusId,