Bump sentence-transformers in /backend/5-studycompass

Bumps [sentence-transformers](https://github.com/UKPLab/sentence-transformers) from 2.4.0 to 2.5.1.
- [Release notes](https://github.com/UKPLab/sentence-transformers/releases)
- [Commits](UKPLab/sentence-transformers@v2.4.0...v2.5.1)

---
updated-dependencies:
- dependency-name: sentence-transformers
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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