FahrplanPanel: Now using isNaN

src/panels/Fahrplan/FahrplanPanel.tsx

@@ -161,7 +161,7 @@ function stringToDelay(input: string): number | undefined {
   if(delay === 0) {
     return undefined;
   }
-  if(delay === Number.NaN) {
+  if(isNaN(delay)) {
     console.warn("While parsing delay, the string was not interpretable as number", input);
     return undefined;
   }