The Multiple SCMs plugin is deprecated, and Jenkins flags an alert if it´s installed. The Build Status Notifier plugin depends on it, so it´s not possible to uninstall the Multiple SCMs plugin as long as the Build Status Notifier plugin is installed.
If the Multiple SCMs plugin is required for some functionality, and the Build Status Notifier plugin cannot be made independent of it, would it at least be possible to make the Multiple SCMs plugin optional, and disable functionality that requires it if it is not installed?