The Labs option Delete dangling commits when over size limit should also run when the repository size is between 2-4 GB but not only 4-10 GB because otherwise the user cannot suppress the warnings on UI.
Implementing BCLOUD-11593 would be ideal. Until then, please includes the soft limit to the auto git-gc.
As the soft limit is only about notice and there's no actual restriction, you can ignore the message and notification. If you still want to suppress the warning, the repository admin needs to contact Atlassian Support.