FML rejects service layer files due to too eager fabric.mod.json check in development environment

[UpcraftLP]

If a service file (that is, a jar that loads on the SERVICES layer and therefore does not require a neoforge.mods.toml file), contains a fabric.mod.json file, this results in a mod loading error despite the actual service implementation being loaded successfully.

This does not seem to occur in production, only in a development workspace.