Group `parent not preloaded` errors in sentry

I still haven't found a moment to look into the exact cases that
causes this error, but we're not loosing any information this way.

In fact, it will be easier to find the right information as we only
need to look to one entry in Sentry.

app/models/concerns/group_descendant.rb

@@ -42,7 +42,7 @@ module GroupDescendant
       parent = child.parent
 
       exception = ArgumentError.new <<~MSG
-        parent: [GroupDescendant: #{parent.inspect}] was not preloaded for [#{child.inspect}]")
+        Parent was not preloaded for child when rendering group hierarchy.
         This error is not user facing, but causes a +1 query.
       MSG
       extras = {
@@ -50,7 +50,7 @@ module GroupDescendant
         child: child.inspect,
         preloaded: preloaded.map(&:full_path)
       }
-      issue_url = 'https://gitlab.com/gitlab-org/gitlab-ce/issues/40785'
+      issue_url = 'https://gitlab.com/gitlab-org/gitlab-ce/issues/49404'
 
       Gitlab::Sentry.track_exception(exception, issue_url: issue_url, extra: extras)
     end