Revert nglview to 3.1.4 (#402)

* Update environment.yml

* Update pyproject.toml

Author: jan-janssen

.ci_support/environment.yml

@@ -7,7 +7,7 @@ dependencies:
 - coverage
 - dscribe =2.1.2
 - matplotlib-base =3.10.6
-- nglview =4.0
+- nglview =3.1.4
 - notebook
 - numpy =2.3.3
 - phonopy =2.43.2

pyproject.toml

@@ -43,7 +43,7 @@ grainboundary = [
     "pymatgen==2025.6.14",
 ]
 pyscal = ["pyscal3==3.3.0"]
-nglview = ["nglview==4.0"]
+nglview = ["nglview==3.1.4"]
 matplotlib = ["matplotlib==3.10.6"]
 plotly = ["plotly==6.3.1"]
 clusters = ["scikit-learn==1.7.2"]