Remove notebooks for deprecated canopy package (#422)

The canopy project has been deprecated and the canopy repository has
been archived.

We need to remove documentation and notebooks teaching people to use it.

Author: jhamon

.github/workflows/test-notebooks-changed.yaml

@@ -32,7 +32,7 @@ jobs:
         id: set-matrix
         run: |
           # Get list of changed .ipynb files
-          CHANGED_NOTEBOOKS=$(git diff --name-only origin/${{ inputs.base_ref }}...HEAD | grep '\.ipynb$' || true)
+          CHANGED_NOTEBOOKS=$(git diff --diff-filter=d --name-only origin/${{ inputs.base_ref }}...HEAD | grep '\.ipynb$' || true)
           if [ -z "$CHANGED_NOTEBOOKS" ]; then
             echo "No notebook changes detected"
             echo "has_changes=false" >> $GITHUB_OUTPUT