Drag Drop: mat-grid-tile does not retain height when being dragged

#### What is the expected behavior?
When dragging an item in a list, element rendered next to the user's cursor should look exactly like the element that is being dragged.

#### What is the current behavior?
Height changes and becomes bigger when item is being dragged

#### What are the steps to reproduce?
I use Mat-Grid-List example available in the docs at https://stackblitz.com/angular/oegmxkolgyr?file=app%2Fgrid-list-overview-example.html

Just display it on one line because of "Drag Drop Sortable, mixed orientation support (#13372 )" bug and add drag/drop like this:

```

1
2
3
4

```


When rowHeight is set to a ratio, height of item being drag changes.

Any solution to keep height at correct ratio?

Inizia riproducendo il problema nello StackBlitz collegato usando il markup mat-grid-list e un rowHeight basato su un rapporto. Esamina l’interazione tra mat-grid-tile e drag/drop durante l’anteprima del trascinamento. Il lavoro è completo quando il tile trascinato mantiene lo stesso rapporto tra altezza e larghezza del tile originale.

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