[FIX] Use scipy.interpolate namespace

Instead of the `scipy.interpolate.ndgriddata` namespace which is now deprecated.

brainstat/mesh/interpolate.py

@@ -13,7 +13,7 @@
 from brainspace.mesh.mesh_io import read_surface
 from brainspace.vtk_interface.wrappers.data_object import BSPolyData
 from nilearn.datasets import load_mni152_brain_mask
-from scipy.interpolate.ndgriddata import LinearNDInterpolator, NearestNDInterpolator
+from scipy.interpolate import LinearNDInterpolator, NearestNDInterpolator
 from scipy.spatial import cKDTree
 
 from brainstat._typing import ArrayLike