ripples (mat-checkbox, mat-option, etc...) cause scrolling in dialog

#### Bug, feature request, or proposal:
If a mat-checkbox is the last element in a mat-dialog-content it will cause the dialog to to have a scrollbar, even if the content has not reached it's max height.

#### What is the expected behavior?

There should be no scrolling if the dialog has room to grow.

#### What is the current behavior?

The dialog scrolls when a mat-checkbox is present.

#### What are the steps to reproduce?
https://stackblitz.com/edit/angular-material2-issue-dhosn1

Click the button, notice the dialog.

#### What is the use-case or motivation for changing an existing behavior?

It looks bad.

#### Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Whatever is used by stackblitz

#### Is there anything else we should know?

Start by reproducing the issue in the linked StackBlitz example, then inspect the interaction between mat-dialog-content and the mat-checkbox ripple when the checkbox is the last element. Done means a dialog with room to grow no longer gets a scrollbar when a mat-checkbox or similar rippled component is present.

Written by the indexing model from the issue text.