Fix breadcrumbs in User Settings

What does this MR do?

Fixes broken breadcrumb text/links in User Settings, as described in #40274 (closed).

This fix mirrors the approach taken to the same problem in numerous other code paths in the app (for example, here).

Not sure if a wider change (for example, adding a helper method to allow an arbitrary trail of breadcrumbs to be defined in a single call, plus a refactor of existing usages) would be desirable - thoughts welcome.

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

Why was this MR needed?

To improve user experience when navigating settings. See original issue for details.

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
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered

What are the relevant issue numbers?

Closes #40274 (closed)