Kindergarten Garden - unused constructor cleanup (#1465)

exercises/kindergarten-garden/src/main/java/KindergartenGarden.java

 
 class KindergartenGarden {
 
-    KindergartenGarden(String garden, String[] students) {
-        throw new UnsupportedOperationException("Delete this statement and write your own implementation.");
-    }
-
     KindergartenGarden(String garden) {
         throw new UnsupportedOperationException("Delete this statement and write your own implementation.");
     }