submodule: bump openthread from `7ec658e` to `6b6edf5` (#160)
submodule: bump openthread from `7ec658e` to `6b6edf5` (#160)

Bumps [openthread](https://github.com/openthread/openthread) from `7ec658e` to `6b6edf5`.
- [Commits](https://github.com/openthread/openthread/compare/7ec658e47a39e1c3c55651e584e0748b259d2d4d...6b6edf53f383ae75511a4f95cad892e58628eb1a)

---
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