Fix token handling for downloading benchmark report in workflow

.github/workflows/docs-and-testcov.yml

@@ -105,6 +105,8 @@ jobs:
           > last-commit-date.json
 
       - name: Download last available benchmark report
+        env:
+          GH_TOKEN: ${{ secrets.CUSTOM_GH_TOKEN }}
         run: |
           artifact_url=$(gh api -H "Accept: application/vnd.github+json" \
             /repos/${{ github.repository }}/actions/artifacts \
@@ -117,7 +119,7 @@ jobs:
             exit 0
           fi
 
-          curl -L -H "Authorization: Bearer ${{ secrets.CUSTOM_GH_TOKEN }}" \
+          curl -L -H "Authorization: Bearer ${GH_TOKEN}" \
           "$artifact_url" -o benchmark-report.zip
 
           # Print all files in the current directory