Shelter radiation_porosity bug when values are mixed floats/ints

[jamesramsden-bh]

To replicate, create a typology where the radiation_porosity type in the first shelter does not match the type of any of the other shelters, e.g.

Typology(
        identifier=f"Test Typology",
        shelters=[
            Shelter.from_adjacent_wall(angle=0, radiation_porosity = (0,) * 8760),
            Shelter.from_adjacent_wall(angle=90, radiation_porosity = (0.0,) * 8760),
        ],
        )

Then run an ExternalComfort with this typology as an input to a SimulationResult. The ExternalComfort will fail. This is because the numpy stuff under the hood can't handle these mixed types. (Specifically, it fails on line 859 of _shelterbase, because numpy gets the object type from the first shelter on line 855.)

Easiest fix: when constructing the shelter, force convert the radiation_porosity to float, or enforce float type in the post init.