Top level group alert saas only

What does this MR do and why?

Alert [#360536 (closed)] informing owner/maintainer role that the new group they've created is a top-level group is displaying to SM instances. It should only display to SaaS namespaces.

Screenshots or screen recordings

affected page

How to set up and validate locally

• Setup gdk to simulate SaaS - https://docs.gitlab.com/ee/development/ee_features.html#simulate-a-saas-instance and restart GDK
• Visit /groups/new#create-group-pane. Make sure alert is present.
• Disable SaaS simulation and restart GDK.
• Visit /groups/new#create-group-pane. Make sure there is no alert.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #395720 (closed)