Generate YAML can be closed with Escape and wipe progress

[Venefilyn]

Describe the bug
When at a project's security page and filling out the Generate YAML form, you can cause it to close by pressing escape. When you've closed it all progress is lost upon clicking the Generate YAML button again.

To Reproduce
Steps to reproduce the behavior:

1. Go to a project's Security page https://insights.linuxfoundation.org/project/cockpit-project-cockpit/repository/cockpit-project_cockpit/security
2. Click on Generate YAML
3. Fill out something basic
4. Press "Escape" on your keyboard and see the form close
5. Click on Generate YAML
6. See all progress wiped

Expected behavior
A warning to appear when about losing progress when

1. Pressing "Escape"
2. Refreshing the page

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Jira Issue: DE-903