submodule: bump third_party/openthread/repo from `39ac118` to `fcbc4be` (#1387)
submodule: bump third_party/openthread/repo from `39ac118` to `fcbc4be` (#1387)

Bumps [third_party/openthread/repo](https://github.com/openthread/openthread) from `39ac118` to `fcbc4be`.
- [Commits](https://github.com/openthread/openthread/compare/39ac118a03766f111a8126df5303d6047f62f26d...fcbc4bef9b634a4d3987fde9ed7f3a954970cd58)

---
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/borderrouter,openthread/ot-br-posix,openthread/borderrouter,openthread/borderrouter,openthread/ot-br-posix,openthread/ot-br-posix,openthread/ot-br-posix,openthread/borderrouter,openthread/borderrouter,openthread/ot-br-posix,openthread/ot-br-posix,openthread/borderrouter