submodule: bump openthread from `d51eb07` to `73f2871` (#252)
submodule: bump openthread from `d51eb07` to `73f2871` (#252)

Bumps [openthread](https://github.com/openthread/openthread) from `d51eb07` to `73f2871`.
- [Commits](https://github.com/openthread/openthread/compare/d51eb07c62d0127c7c854fc0bfd06a9f00b2a681...73f28712b29e96500a8c1be3198989559f365d8d)

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

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
openthread/ot-kw41z,openthread/ot-kw41z