Bump third_party/mbedtls/repo from 0834c59 to 2153b1b (#37736)

Bumps [third_party/mbedtls/repo](https://github.com/ARMmbed/mbedtls) from `0834c59` to `2153b1b`.
- [Release notes](https://github.com/ARMmbed/mbedtls/releases)
- [Commits](Mbed-TLS/mbedtls@0834c59...2153b1b)

---
updated-dependencies:
- dependency-name: third_party/mbedtls/repo
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]