Conflict in unit alias

Reproduce the example using Pint's application_registry, NumPy, and the cf_xarray.units import shown in the report, then inspect how the CF units are registered and how the electron-volt alias changes. Done means the documented conversion from electron temperature to thermal velocity still converts to km/s after importing cf_xarray.units, with a regression check for the reported conflict.

Take a conversion from electron temperature to thermal velocity as an example:

from pint import application_registry as u
import numpy as np
np.sqrt(100 * u.eV / u.m_e).to("km/s")
# <Quantity(4193.82881, 'kilometer / second')>

If we then import cf_xarray.units to enable CF units, per this page, we get the following error:

import cf_xarray.units
np.sqrt(100 * u.eV / u.m_e).to("km/s")

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/tvo/.local/share/mamba/envs/test_xarray_units/lib/python3.12/site-packages/pint/facets/plain/quantity.py", line 536, in to
    magnitude = self._convert_magnitude_not_inplace(other, *contexts, **ctx_kwargs)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tvo/.local/share/mamba/envs/test_xarray_units/lib/python3.12/site-packages/pint/facets/plain/quantity.py", line 480, in _convert_magnitude_not_inplace
    return self._REGISTRY.convert(self._magnitude, self._units, other)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tvo/.local/share/mamba/envs/test_xarray_units/lib/python3.12/site-packages/pint/facets/plain/registry.py", line 1041, in convert
    return self._convert(value, src, dst, inplace)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tvo/.local/share/mamba/envs/test_xarray_units/lib/python3.12/site-packages/pint/facets/context/registry.py", line 405, in _convert
    return super()._convert(value, src, dst, inplace)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tvo/.local/share/mamba/envs/test_xarray_units/lib/python3.12/site-packages/pint/facets/nonmultiplicative/registry.py", line 259, in _convert
    return super()._convert(value, src, dst, inplace)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tvo/.local/share/mamba/envs/test_xarray_units/lib/python3.12/site-packages/pint/facets/plain/registry.py", line 1076, in _convert
    raise factor
pint.errors.DimensionalityError: Cannot convert from 'electron_volt ** 0.5 / electron_mass ** 0.5' ([temperature] ** 0.5 * [length] / [time] ** 1.5 / [current] ** 0.5) to 'kilometer / second' ([length] / [time])