[terra-application-v3] Implement new modal content UI

[ryanthemanuel]

Story

JIRA: UXPLATFORM-5457

Description

As a consumer of terra, I would like to be able to use new look and feel for modal content inside of terra application

Motivation

So that I am complying with the latest design standards for modal content

Definition of Done

We'll know we're done when the modal content UI is available for consumers to use