add _magnitude to ureg().to() when passing arrays to ase.Atoms

[mdforti]

as mentioned here;

#71

this warnings are raised when normalizing vasp outputs in script:

'''
/scratch/AnacondaEnvironments/anaconda3/envs/nomad/lib/python3.9/site-packages/ase/cell.py:97: UnitStrippedWarning: The unit of the quantity is stripped when downcasting to ndarray.
cell = np.array(cell, float)
'''

'''
/scratch/AnacondaEnvironments/anaconda3/envs/nomad/lib/python3.9/site-packages/ase/atoms.py:424: UnitStrippedWarning: The unit of the quantity is stripped when downcasting to ndarray.
a = np.array(a, dtype, order='C')
'''

this fixes:

1e2200c

[lauri-codes]

This is now fixed in the develop branch by this commit.