Related to https://github.com/fleetdm/fleet/issues/10299, this allows to
start the Fleet server with MDM enabled without having to provide ABM
configs.
I have tested this with:
1. Premium account, no ABM config: the server starts normally, but
without ABM features
2. Premium account, invalid ABM config: error starting the server
3. Premium account, valid ABM config: ABM features enabled
4. Free account, no ABM config: the server starts normally
5. Free account, any ABM config: error due to invalid license