[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

Inizia riproducendo in Safari l'esempio della sezione “Scrolling to an element” della documentazione beta di React, quindi confrontalo con challenge 3, che utilizza lo stesso principio di scorrimento. Analizza il comportamento di overflow segnalato e verifica che entrambi gli esempi funzionino come previsto quando si fa clic sui relativi pulsanti, senza modificare manualmente gli stili.