Angular velocity returns dimensionless

[tsaubergine]

required int32 angular_vel = 4 [
    (dccl.field) = { units { system: "angle::degree" derived_dimensions: "angular_velocity" } }

ends up providing a dimensionless value (which leads to incorrect conversions).

[tsaubergine]

It appears this is a dimension but ill-defined so conversions are allowed but don't work correctly. We need some way to check for this poorly defined systems.