Thermal model tests unexpected behavior

[augustjohansson]

The test_thermal_validation.jl is not included in the runtests.jl, and yields an error:

KeyError: key "SurfaceHeatTransferCoefficient" not found

I can change the json to have the correct key, but the interesting thing is that test_thermal.jl runs fine with the same json.

[LorenaH84]

I think I haven't updated after the latest changes in the thermal model, so probably something has to be updated. Will have a look in the near future