submodule: bump openthread from 9099a13 to 0c5966d

Bumps [openthread](https://github.com/openthread/openthread) from `9099a13` to `0c5966d`.
- [Release notes](https://github.com/openthread/openthread/releases)
- [Commits](openthread/openthread@9099a13...0c5966d)

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

Signed-off-by: dependabot[bot] <[email protected]>