submodule: bump openthread from 151444f to 1024a1f (#867)

Bumps [openthread](https://github.com/openthread/openthread) from `151444f` to `1024a1f`.
- [Commits](openthread/openthread@151444f...1024a1f)

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

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