build(deps): bump sphinx-notfound-page in /requirements (#465)

Bumps [sphinx-notfound-page](https://github.com/readthedocs/sphinx-notfound-page) from 1.0.3 to 1.0.4.
- [Changelog](https://github.com/readthedocs/sphinx-notfound-page/blob/main/CHANGELOG.rst)
- [Commits](readthedocs/sphinx-notfound-page@1.0.3...1.0.4)

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

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

requirements/requirements_doc.txt

@@ -7,6 +7,6 @@ pypandoc==1.13
 pyvista==0.43.9
 sphinx-copybutton==0.5.2
 sphinx-gallery==0.17.0
-sphinx-notfound-page==1.0.3
+sphinx-notfound-page==1.0.4
 trame==3.6.3
 vtk==9.3.1