Frontend: When .gitlab-ci.yml is externally managed, users are still prompted to try a gitlab-ci.yml and then being told they cannot

Summary

When .gitlab-ci.yml location is externally managed, the user is still prompted to setup a `gitlab-ci.yml` file and then told that they cannot:

Steps to reproduce

1. From the UI, in a project, go to Settings -> CI/CD -> expand General pipeline:
2. In the CI/CD configuration file field put the location of another projects gitlab-ci.yml and save.
3. Go to Build and then choose Pipelines
4. Click the blue button near the top that says "Try test template"
5. Receive message that this is externally managed.

Example Project

https://gitlab.com/gitlab-gold/gyoachum/test-group/borrowedcicd1

What is the current bug behavior?

Users are prompted to try out a gitlab-ci.yml, and then are told they can't, because this is externally managed.

What is the expected correct behavior?

Users should not be prompted to try out a gitlab-ci.yml, at all, if this is externally managed.

Relevant logs and/or screenshots

Output of checks

Happens on GitLab.com. See example project above ^

Possible fixes

We can show different screens other than the onboarding screen in the Build > Pipelines not to prompt the onboarding screen.

Pipeline empty state

• Figma Prototype