This change converts the DraftReviewRequest resource model to

TypeScript.
The one complication in here is a change in behavior with mixins

where the url() implementation in DraftResourceModelMixin was

taking priority over the one in DraftReviewRequest. In the vast

majority of draft resource cases, the implementation in the mixin

is what we want, but review requests are special.

Ran js-tests.
Ran setup.py build_media.