chore(deps): bump undici and testcontainers

Bumps [undici](https://github.com/nodejs/undici) to 8.12.3 and updates ancestor dependency [testcontainers](https://github.com/testcontainers/testcontainers-node). These dependencies need to be updated together.


Updates `undici` from 5.29.0 to 8.12.3
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v5.29.0...v8.12.3)

Updates `testcontainers` from 10.28.0 to 12.2.1
- [Release notes](https://github.com/testcontainers/testcontainers-node/releases)
- [Commits](testcontainers/testcontainers-node@v10.28.0...v12.2.1)

---
updated-dependencies:
- dependency-name: undici
  dependency-version: 8.12.3
  dependency-type: indirect
- dependency-name: testcontainers
  dependency-version: 12.2.1
  dependency-type: direct:development
...

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Author: dependabot[bot]