Pipeline UI with outboard configuration and no executed pipelines does not recognize pipeline definitions

When you have a project configured to use an outboard CI configuration file (e.g. pipeline.yml@other/project:my_branch), but no pipelines have yet run, the Web UI does not offer the option to trigger a pipeline, but instead attempts to induce the user to create CI/CD definitions.

One would expect the UI to understand the outboard definition, and offer the user to trigger a job - same as when some pipelines have already been triggered.