Bump starlette in /cloud-run-rag-alloydb/1-apps/apps/rag/frontend (#123)

Bumps [starlette](https://github.com/Kludex/starlette) from 0.46.2 to 0.49.1.
- [Release notes](https://github.com/Kludex/starlette/releases)
- [Changelog](https://github.com/Kludex/starlette/blob/main/docs/release-notes.md)
- [Commits](Kludex/starlette@0.46.2...0.49.1)

---
updated-dependencies:
- dependency-name: starlette
  dependency-version: 0.49.1
  dependency-type: indirect
...

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Author: dependabot[bot]