fix(core_class): Drop plot_with_threejs import.

Author: daavoo

src/pyntcloud/core_class.py

@@ -9,7 +9,6 @@
 from .neighbors import k_neighbors, r_neighbors
 from .plot import DESCRIPTION, AVAILABLE_BACKENDS
 from .plot.matplotlib_backend import plot_with_matplotlib
-from .plot.threejs_backend import plot_with_threejs
 from .plot.pythreejs_backend import plot_with_pythreejs
 from .plot.pyvista_backend import plot_with_pyvista
 from .samplers import ALL_SAMPLERS