Harmonic: validation is complaining when dielectric is not in input

[bastonero]

Some validation port (e.g. the one for dielectric.property) must be deactivated somehow, otherwise when dielectric is not in input (which should be possible to do), it complains of validating some remaining ports. It might also be possible that this is solved is some newer aiida-core versions.

Still, one can use the PhononWorkChain, which is thought to do the phonon part only.