integrate recommendations from rubocop

plugins/messages/app/controllers/messages_controller.rb

@@ -34,17 +34,15 @@ def create
     ActiveRecord::Base.transaction do
       @current_user.with_lock do
         @message = @current_user.send_messages.new(params[:message])
-        if @message.save
-          DeliverMessageJob.perform_later(@message)
-          redirect_to messages_url, notice: I18n.t('messages.create.notice')
-        else
-          raise ActiveRecord::Rollback # Rollback the transaction if the save fails
-        end
+        raise ActiveRecord::Rollback unless @message.save
+
+        DeliverMessageJob.perform_later(@message)
+        redirect_to messages_url, notice: I18n.t('messages.create.notice')
       end
     end
-    rescue ActiveRecord::RecordInvalid => e
-      # Handle validation errors
-      render action: 'new'
+  rescue ActiveRecord::RecordInvalid
+    # Handle validation errors
+    render action: 'new'
   end
 
   # Shows a single message.