Bump ansys-sphinx-theme from 0.10.3 to 0.12.2 in /requirements

Bumps [ansys-sphinx-theme](https://github.com/ansys/ansys-sphinx-theme) from 0.10.3 to 0.12.2.
- [Release notes](https://github.com/ansys/ansys-sphinx-theme/releases)
- [Commits](ansys/ansys-sphinx-theme@v0.10.3...v0.12.2)

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

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

requirements/requirements_doc.txt

@@ -11,7 +11,7 @@ vtk==9.2.6
 # Documentation dependencies
 Sphinx==7.1.2
 numpydoc==1.5.0
-ansys-sphinx-theme==0.10.3
+ansys-sphinx-theme==0.12.2
 sphinx-copybutton==0.5.2
 jupyter_sphinx==0.4.0
 jupyterlab>=3.2.8