Simplified fetching

new-frontend/src/components/XmlTool.vue

@@ -23,10 +23,9 @@ async function submit() {
   });
 
 
-  var responseBody = await fetch(request).then(async response => {
-    const text = await response.text();
-    return JSON.parse(text);
-  });
+  var responseBody = await fetch(request)
+    .then(response => response.json())
+    .then((body) => body);
 
   result.value = responseBody.result;
 }