Update notebooks and workflow to install mace torch.

Author: shyuep

.github/workflows/test-nbs.yml

@@ -33,7 +33,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          pip install dgl==2.4.0 -f https://data.dgl.ai/wheels/torch-2.4/repo.html
+          pip install mace-torch
           pip install -e '.[ci]'
 
       - name: Execute all notebook examples