build(deps-dev): bump ansys-sphinx-theme from 0.11.2 to 0.12.1

Bumps [ansys-sphinx-theme](https://github.com/ansys/ansys-sphinx-theme) from 0.11.2 to 0.12.1.
- [Release notes](https://github.com/ansys/ansys-sphinx-theme/releases)
- [Commits](ansys/ansys-sphinx-theme@v0.11.2...v0.12.1)

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

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

pyproject.toml

@@ -59,7 +59,7 @@ doc = [
     "sphinx-copybutton==0.5.2",
     "sphinx-gallery==0.14.0",
     "sphinx-autodoc-typehints==1.24.0",
-    "ansys-sphinx-theme==0.11.2",
+    "ansys-sphinx-theme==0.12.1",
     "pypandoc==1.11",
     "nbsphinx==0.9.3",
     "ipywidgets==8.1.1",