Save IP address used for sign-up, not only sign-in (mastodon#10026)

Fixes mastodon#9995

Author: ClearlyClaire

app/controllers/auth/registrations_controller.rb

@@ -28,6 +28,7 @@ def build_resource(hash = nil)
     resource.invite_code = params[:invite_code] if resource.invite_code.blank?
     resource.agreement   = true
 
+    resource.current_sign_in_ip = request.remote_ip if resource.current_sign_in_ip.nil?
     resource.build_account if resource.account.nil?
   end