Now that I've introduced Leonbergers, I figured we should add their health screenings

These are the current health tests for the breed.
Autoimmune Thyroiditis
Leonberger Polyneuropathy (LPN1)
Leonberger Polyneuropathy 2 (LPN2)
Laryngeal Paralysis and Polyneuropathy (LPPN3)
Leukoencephalomyelopathy (LEMP)
Congenital Cardiac Disease