title: Rxjs toPromise() deprecated
body: <p>I have read that <code>toPromise()</code> is being deprecated in RxJS 7 and will be removed in RxJS 8.
  I have often used it with async await syntax in angular to handle http calls. Is it considered an anti pattern?
  I understand the concept of streams but an http call only emit a single value. I don't get the point of observable for a simple http call. What should I use next? should I fully embrace reactive programming?</p>