feat: improve secondary indices for self service tables

[aeneasr]

Related issue(s)

https://github.com/ory-corp/cloud/issues/7199

Checklist

• [ ] I have read the contributing guidelines.
• [ ] I have referenced an issue containing the design document if my change introduces a new feature.
• [ ] I am following the contributing code guidelines.
• [ ] I have read the security policy.
• [ ] I confirm that this pull request does not address a security vulnerability. If this pull request addresses a security vulnerability, I confirm that I got the approval (please contact security@ory.sh) from the maintainers to push the changes.
• [ ] I have added tests that prove my fix is effective or that my feature works.
• [ ] I have added or changed the documentation.

Further Comments

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.56%. Comparing base (b4c453b) to head (21b3837). Report is 4 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #4179 +/- ## ========================================== - Coverage 78.57% 78.56% -0.02% ========================================== Files 379 379 Lines 27042 27042 ========================================== - Hits 21249 21245 -4 - Misses 4181 4184 +3 - Partials 1612 1613 +1 ```

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