Bump urllib3 from 2.5.0 to 2.6.3 in /notebook_python

Bumps [urllib3](https://github.com/urllib3/urllib3) from 2.5.0 to 2.6.3.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@2.5.0...2.6.3)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-version: 2.6.3
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

notebook_python/requirements_notebook.txt

@@ -86,7 +86,7 @@ traitlets==5.14.3
 types-python-dateutil==2.9.0.20250822
 typing_extensions==4.15.0
 uri-template==1.3.0
-urllib3==2.5.0
+urllib3==2.6.3
 wcwidth==0.2.14
 webcolors==24.11.1
 webencodings==0.5.1