Fix import groupings to satisfy corrected goimports linter settings

[avanderbergh]

Fix import groupings to satisfy corrected goimports linter settings

Description

The goimports.local-prefixes setting was incorrect, so local import groupings was not applied correctly.

relates to #6103

Since this is just a tooling / cosmetic change and does not affect any compiled code, I did not update the changelog. Please let me know if this is necessary.

Checklist

• Issue was linked above
• No generated code was adjusted manually (check comments in file header)
• Changelogs
  • Changelog in the root directory was adjusted (see here)
  • Changelog(s) of the service(s) were adjusted (see e.g. here)
• VERSION file(s) of the service(s) were adjusted
• Code format was applied: make fmt
• Examples were added / adjusted (see examples/ directory)
• Unit tests got implemented or updated
• Unit tests are passing: make test (will be checked by CI)
• No linter issues: make lint (will be checked by CI)

[cgoetz-inovex]

Thank you for your contribution!