submodule: bump third_party/openthread/repo from 24e9306 to `1a2d5f…

…0` (#2454)

Bumps [third_party/openthread/repo](https://github.com/openthread/openthread) from `24e9306` to `1a2d5f0`.
- [Commits](openthread/openthread@24e9306...1a2d5f0)

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

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