Bump ansys-sphinx-theme from 0.12.2 to 0.12.4 in /requirements

Bumps [ansys-sphinx-theme](https://github.com/ansys/ansys-sphinx-theme) from 0.12.2 to 0.12.4.
- [Release notes](https://github.com/ansys/ansys-sphinx-theme/releases)
- [Commits](ansys/ansys-sphinx-theme@v0.12.2...v0.12.4)

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

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

Author: dependabot[bot]

requirements/requirements_doc.txt

@@ -1,6 +1,6 @@
 Sphinx==7.2.6
 numpydoc==1.5.0
-ansys-sphinx-theme==0.12.2
+ansys-sphinx-theme==0.12.4
 sphinx-copybutton==0.5.2
 apispec==6.3.0
 sphinxcontrib-httpdomain==1.8.1