A Phase 2, Multicenter, Double-Blind, Randomized, Placebo-controlled Trial, Evaluating Safety, Tolerability, and Efficacy of Subcutaneous Doses of TransCon CNP Administered Once Weekly for 52 Weeks in Infants (0 to <2 Years of Age) With Achondroplasia Followed by an Open Label Extension (OLE) Period | Arctuva