Bump jupyterlab from 4.4.4 to 4.4.8 in /images/singleuser-sample

Bumps [jupyterlab](https://github.com/jupyterlab/jupyterlab) from 4.4.4 to 4.4.8.
- [Release notes](https://github.com/jupyterlab/jupyterlab/releases)
- [Changelog](https://github.com/jupyterlab/jupyterlab/blob/main/RELEASE.md)
- [Commits](https://github.com/jupyterlab/jupyterlab/compare/@jupyterlab/[email protected]...@jupyterlab/[email protected])

---
updated-dependencies:
- dependency-name: jupyterlab
  dependency-version: 4.4.8
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

images/singleuser-sample/requirements.txt

@@ -139,7 +139,7 @@ jupyter-server-terminals==0.5.3
     # via jupyter-server
 jupyterhub==5.3.0
     # via -r unfrozen/requirements.txt
-jupyterlab==4.4.4
+jupyterlab==4.4.8
     # via -r unfrozen/requirements.txt
 jupyterlab-pygments==0.3.0
     # via nbconvert