Gallery - Mojo is no more using quarto

closes quarto-dev/quarto-cli#10980

(cherry picked from commit 7c54de1)

Author: cderv

docs/gallery/gallery.yml

@@ -196,10 +196,6 @@
       href: https://quarto.org
       code: https://github.com/quarto-dev/quarto-web/
       thumbnail: websites/websites-quarto.png
-    - title: "Mojo"
-      subtitle: Documentation
-      href: https://docs.modular.com/mojo/
-      thumbnail: websites/websites-mojo.png
     - title: NASA & OpenScapes
       subtitle: website
       href: https://nasa-openscapes.github.io/