[6.15.z] Bump sphinx from 7.3.4 to 7.3.6 (#14830)

Bump sphinx from 7.3.4 to 7.3.6 (#14828)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.3.4 to 7.3.6.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v7.3.4...v7.3.6)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
(cherry picked from commit 5c7abc1)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements-optional.txt

@@ -5,7 +5,7 @@ redis==5.0.3
 pre-commit==3.7.0
 
 # For generating documentation.
-sphinx==7.3.4
+sphinx==7.3.6
 sphinx-autoapi==3.0.0
 
 # For 'manage' interactive shell