[forge] Enable ONLY_SHOW_RELEVANT_REPOS UI setting

- Set ONLY_SHOW_RELEVANT_REPOS to true to improve user experience
- Only shows repositories relevant to the user's context

Resolves: https://codeberg.org/fedora/forgejo-deployment/issues/172

roles/openshift-apps/forgejo/templates/values.yaml.j2

@@ -494,7 +494,8 @@ gitea:
     cors: {}
 
     ## @param gitea.config.ui User interface settings
-    ui: {}
+    ui:
+      ONLY_SHOW_RELEVANT_REPOS: true
 
     ## @param gitea.config.markdown Markdown parser settings
     markdown: {}