Update Registration Features CTA for repository size limit
Related to #341949 (closed).
We need to update the method to show the Registration Features CTA used at !73222 (merged). This requires:
- Adding CE templates with only the CTA (one for groups and projects settings, and one for application settings)
- Add content-based tests for the CTA behavior.
- Use the new
registration_features_can_be_promptedhelper.