fix(a11y): remove listeners when focus trap anchors are removed (#14629)
fix(a11y): remove listeners when focus trap anchors are removed (#14629)

Fixes the `focus` event handlers, which retain a reference to the focus trap, not being cleaned up from the focus trap anchor elements on destroy.
DevVersion/material2,DevVersion/material2,crisbeto/material2,angular/components,mmalerba/material2,Jefiozie/material2,mmalerba/material2,crisbeto/material2,josephperrott/material2,Jefiozie/material2,crisbeto/material2,andrewseguin/material2,andrewseguin/material2,jelbourn/material2,DevVersion/material2,angular/components,josephperrott/material2,jelbourn/material2,jelbourn/material2,mmalerba/material2,Jefiozie/material2,jelbourn/material2,andrewseguin/material2,Jefiozie/material2,andrewseguin/material2,jelbourn/material2,josephperrott/material2,josephperrott/material2,josephperrott/material2,Jefiozie/material2,DevVersion/material2,angular/components,andrewseguin/material2,DevVersion/material2,crisbeto/material2,angular/components,mmalerba/material2,mmalerba/material2