Bump sphinx from 7.1.2 to 7.2.6 in /tests

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.1.2 to 7.2.6.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES)
- [Commits](sphinx-doc/sphinx@v7.1.2...v7.2.6)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

tests/requirements-test.txt

@@ -1,7 +1,7 @@
 # micro-language and markers are described here: https://www.python.org/dev/peps/pep-0496/
 pytest==7.4.2
 flake8==6.1.0
-sphinx==7.1.2
+sphinx==7.2.6
 mcpl==1.6.2
 pre-commit==3.4.0
 yapf==0.40.2