Avoid numpy scalar warnings (#1880)

NumPy as of 1.25 deprecated automatically converting any "scalar" with
non-zero number of dimensions to a float value. Therefore, we should
ensure our values have ndim == 0 before passing to math.isnan()

pint/facets/numpy/quantity.py

@@ -266,7 +266,7 @@ def __setitem__(self, key, value):
                 isinstance(self._magnitude, np.ma.MaskedArray)
                 and np.ma.is_masked(value)
                 and getattr(value, "size", 0) == 1
-            ) or math.isnan(value):
+            ) or (getattr(value, "ndim", 0) == 0 and math.isnan(value)):
                 self._magnitude[key] = value
                 return
         except TypeError: