Rotation3DToGWAConverter raises an error on length-one angle lists

[emolter]

Minimum example:

import stdatamodels.jwst.datamodels as dm
from stdatamodels.jwst.transforms import Rotation3DToGWA
wcs = Rotation3DToGWA(angles=[45,], axes_order="y")
model = dm.ImageModel((10,10))
model.meta.wcs = wcs

raises a long traceback, with the relevant portion being

    node = {"angles": list(model.angles.value)}
                      ~~~~^^^^^^^^^^^^^^^^^^^^
TypeError: 'numpy.float64' object is not iterable

I'd expect this to work without any issues; using this class to do a single rotation should not be a problem, and indeed until the conversion is attempted this works fine.

By contrast doing

import stdatamodels.jwst.datamodels as dm
from stdatamodels.jwst.transforms import Rotation3DToGWA
wcs = Rotation3DToGWA(angles=[45,0], axes_order="yy")
model = dm.ImageModel((10,10))
model.meta.wcs = wcs

works fine.