submodule: bump openthread from 24e9306 to 1a2d5f0 (#874)

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

---
updated-dependencies:
- dependency-name: openthread
  dependency-type: direct:production
...

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