Only consider valid invite links in registration controller

Author: ClearlyClaire

app/controllers/auth/registrations_controller.rb

@@ -91,7 +91,8 @@ def set_body_classes
   end
 
   def set_invite
-    @invite = invite_code.present? ? Invite.find_by(code: invite_code) : nil
+    invite = invite_code.present? ? Invite.find_by(code: invite_code) : nil
+    @invite = invite&.valid_for_use? ? invite : nil
   end
 
   def determine_layout