fix(drag-drop): dragging class not being applied on drop container (#12921)
fix(drag-drop): dragging class not being applied on drop container (#12921)

Fixes the `cdk-drop-dragging` class not being applied to the drop container after 5d0ec23b1d258504ab786e76f80bd9a1a76cd052. The introduction of the `onStable` call caused the event to be bound outside the `NgZone`.
Jefiozie/material2,josephperrott/material2,angular/components,mmalerba/material2,crisbeto/material2,DevVersion/material2,DevVersion/material2,Jefiozie/material2,josephperrott/material2,andrewseguin/material2,angular/components,angular/components,Jefiozie/material2,josephperrott/material2,Jefiozie/material2,mmalerba/material2,DevVersion/material2,jelbourn/material2,crisbeto/material2,andrewseguin/material2,DevVersion/material2,josephperrott/material2,josephperrott/material2,angular/components,jelbourn/material2,jelbourn/material2,mmalerba/material2,crisbeto/material2,andrewseguin/material2,DevVersion/material2,jelbourn/material2,crisbeto/material2,mmalerba/material2,mmalerba/material2,Jefiozie/material2,andrewseguin/material2,andrewseguin/material2,jelbourn/material2