mat-dialog-content bottom edge scroll blocked on iPhone

#### What is the expected behavior?
Scroll at the edges(bottom edge, top edge) of dialog content not blocked..

#### What is the current behavior?
When I test your example Dialog with header, scrollable content and actions - on iPhone - and I scroll and reach the bottom of the scrollable content - when I by accident try to scroll once more towards the bottom - the scroll becomes unresponsive and I cant scroll up or down until I wait one second or more and try to scroll again towards the top...

#### What are the steps to reproduce?
https://stackblitz.com/angular/nqvvaaopbel?file=app%2Fdialog-content-example.ts
Scroll till the bottom end, and when You reach the bottom and scroll bar dissapears - try to scroll again towards bottom - at that moment scroll is blocked (off course you cant scroll towards the bottom because you reached the end - BUT at that moment you ALSO CANT SCROLL TOWARDS THE TOP and seems like scroll is unresponsive until you stop touching the screen for a short time - for example 1second (or little bit less maybe)...

#### Which versions of Angular, Material, OS, TypeScript, browsers are affected?
I tested it on IPhone, Safari, version 12.1...

#### Is there anything else we should know?

Inizia con il Dialog di StackBlitz collegato, con intestazione, contenuto scorrevole e azioni, quindi analizza il comportamento dello scorrimento di mat-dialog-content su iPhone Safari. Il lavoro è completato quando lo scorrimento rimane reattivo dopo aver raggiunto uno dei due estremi, anche quando viene effettuato uno swipe aggiuntivo verso il fondo.

Scritto dal modello di indicizzazione a partire dal testo della issue.