submodule: bump third_party/openthread/repo from `b9fadd2` to `961fd9a` (#1017)
submodule: bump third_party/openthread/repo from `b9fadd2` to `961fd9a` (#1017)

Bumps [third_party/openthread/repo](https://github.com/openthread/openthread) from `b9fadd2` to `961fd9a`.
- [Commits](https://github.com/openthread/openthread/compare/b9fadd227bc8f95cb1f79b0c223bc765d389d78e...961fd9ae955fc6992953224bc53a6d3644ba715d)

---
updated-dependencies:
- dependency-name: third_party/openthread/repo
  dependency-type: direct:production
...

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

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