Dev Spaces supports only che-code:latest editor. Let's remove che-code:insiders from the list of editors: https://github.com/redhat-developer/devspaces/blob/devspaces-3-rhel-8/dependencies/che-plugin-registry/che-editors.yaml#L112

Also need to remove che-code:insiders from the devworkspace generation process: https://github.com/redhat-developer/devspaces/blob/devspaces-3-rhel-8/dependencies/che-devfile-registry/build/scripts/generate_devworkspace_templates.sh#L49