Dinosaur Explore entities don't render properly

Summary: All entities that we replaced with our own models (e.g. dinosaurs, vehicles etc) don't work anymore in Dinosaur Explore. They look very weird.

Verification builds: 1.12

Impact: Pigs, llamas and so on which we replaced with dinosaurs and vehicles for Dinosaur Explore doesn't work anymore.

Repro Steps:

1. Load Dinosaur Explore with the world template.
2. Find any dinosaur in the zoo, or use a spawn egg in creative mode to spawn one (e.g. Stegosaurus).

Observed Results:

Spawns a weird looking entity.

Expected Results: Should spawn a dinosaur.

Screenshots/Videos attached: Yes