[docs beta] "Scrolling to an element" example does not work on Safari

Checking the beta docs, I noticed that one of the examples was not working. At first it was not working at all, but after I added a style of overflow-x: auto to the <ul> element, then I could see the desired effect after clicking on the buttons. I could later check that the example works as expected (without any changes in Chrome). My first guess is that Safari doesn't scroll because the element has an implicit overflow as visible.

Please note that this issue is also present on the challenge 3, as it basically uses that same principle to scroll the images.

Steps

1. Open https://beta.reactjs.org/learn/manipulating-the-dom-with-refs#example-scrolling-to-an-element on Safari
2. Click on the buttons

Beginne damit, das Beispiel aus dem Abschnitt „Scrolling to an element“ der Beta-React-Dokumentation in Safari zu reproduzieren, und vergleiche es anschließend mit challenge 3, das dasselbe Scrollprinzip verwendet. Untersuche das gemeldete Overflow-Verhalten und überprüfe, dass beide Beispiele wie erwartet funktionieren, wenn ihre Schaltflächen angeklickt werden, ohne manuelle Stiländerungen vorzunehmen.