Fix #48934 - Focus on text input on danger confirmation

What does this MR do?

Improves the danger confirmation modals by focusing on the text input field.

The issue just mentions one instance of this, but at implementation time I found that it's used in a few places. I've accordingly added tests to these places.

Are there points in the code the reviewer needs to double check?

Did I miss somewhere that these modals are used? If so, maybe we need a spec there too.

Why was this MR needed?

UX improvement, see issue.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Conform by the merge request performance guides
• Conform by the style guides
• Conform by the database guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?