refactor: simplify DigitalClock and TimeConverter components

src/containers/DigitalClock.tsx

@@ -25,7 +25,6 @@ export function DigitalClock({
 
   return (
     <div>
-      <span data-testid="digital-clock">{dateToDigital(currentTime)}</span>
       <input
         data-testid="time-input"
         type="text"

src/containers/TimeConverter.tsx

@@ -6,7 +6,7 @@ import { dateToBerlin } from "../utils";
 
 export function TimeConverter() {
   const { currentTime, setCurrentTime } = useCurrentTime();
-  const [useSystemTime, setUseSystemTime] = useState(false);
+  const [useSystemTime, setUseSystemTime] = useState(true);
   const berlinClock = dateToBerlin(currentTime);
 
   useEffect(() => {
@@ -18,7 +18,7 @@ export function TimeConverter() {
   }, [useSystemTime, setCurrentTime]);
 
   return (
-    <div>
+    <div className="time-converter">
       <BerlinClock enabled={true} clock={berlinClock} />
       <DigitalClock
         currentTime={currentTime}