Uniform contributor invite endpoints

VRE/apps/study/urls.py

@@ -5,7 +5,6 @@ from .views import Contributors, process_study_invite, validate_study_invite
 urlpatterns = [
     path('<int:study_id>/contributors/', Contributors.as_view({'get': 'list'}), name='study-contributors'),
     path('<int:study_id>/contributors/<int:contributor_id>/', Contributors.as_view({'get': 'get', 'put': 'update', 'post': 'update', 'delete': 'delete'}), name='study-contributors'),
-
-    path('<int:study_id>/contributor/invite/', process_study_invite, name='study-invite'),
-    path('<int:study_id>/join/<path:jwt_token>', validate_study_invite, name='study-invite-join'),
+    path('<int:study_id>/contributors/invite/', process_study_invite, name='study-invite'),
+    path('<int:study_id>/contributors/join/<path:jwt_token>', validate_study_invite, name='study-invite-join'),
 ]