submodule: bump openthread from `dbcebd2` to `4747a9c` (#243)
submodule: bump openthread from `dbcebd2` to `4747a9c` (#243)

Bumps [openthread](https://github.com/openthread/openthread) from `dbcebd2` to `4747a9c`.
- [Commits](https://github.com/openthread/openthread/compare/dbcebd2ed4f1c8fbd77252f72177c83af767fc33...4747a9c77657fa4b86f2e540ec3af3db94095ea3)

---
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-b91,openthread/ot-b91