build: fix error in expansion panel examples (#15565)
build: fix error in expansion panel examples (#15565)

Fixes errors in a couple of errors that started being thrown by a couple of the expansion panel examples after we started lazy-loading the routes.
josephperrott/material2,crisbeto/material2,angular/components,DevVersion/material2,mmalerba/material2,andrewseguin/material2,Jefiozie/material2,Jefiozie/material2,angular/components,josephperrott/material2,crisbeto/material2,jelbourn/material2,andrewseguin/material2,DevVersion/material2,DevVersion/material2,mmalerba/material2,josephperrott/material2,josephperrott/material2,Jefiozie/material2,andrewseguin/material2,crisbeto/material2,angular/components,DevVersion/material2,jelbourn/material2,mmalerba/material2,jelbourn/material2,jelbourn/material2,Jefiozie/material2,crisbeto/material2,Jefiozie/material2,mmalerba/material2,DevVersion/material2,angular/components,andrewseguin/material2,mmalerba/material2,andrewseguin/material2,jelbourn/material2,josephperrott/material2