Fix eventduration shown in edit event (#2037)

* Fix eventduration shown in edit event

* Fix eventduration to round to a whole number

Author: hei98

frontend/src/PagesAdmin/EventCreatorAdminPage/EventCreatorAdminPage.tsx

@@ -115,7 +115,9 @@ export function EventCreatorAdminPage() {
     if (id) {
       getEvent(id)
         .then((eventData) => {
-          const eventDuration = new Date(eventData.end_dt).getTime() - new Date(eventData.start_dt).getTime();
+          const eventDuration = Math.round(
+            (new Date(eventData.end_dt).getTime() - new Date(eventData.start_dt).getTime()) / 60000,
+          );
           const imageObject: ImageDto | undefined = eventData.image_url
             ? { id: eventData.id, title: '', url: eventData.image_url, tags: [] }
             : undefined;