Bump Jupyter Core to 5.8.1 based on CVE-2025-30167

Updating Jupyter Core to address the CVE-2025-30167 (see GHSA-33p9-3p43-82vq)

Author: jesuino

etc/generic/requirements-elyra.txt

@@ -4,7 +4,7 @@ ipython==8.12.3
 ipython-genutils==0.2.0
 jinja2==3.1.6
 jupyter-client==7.4.9
-jupyter-core==5.3.1
+jupyter-core==5.8.1
 MarkupSafe==2.1.1
 minio==7.1.15
 nbclient==0.6.3