submodule: bump openthread from 45c5fe4 to f9349c1

Bumps [openthread](https://github.com/openthread/openthread) from `45c5fe4` to `f9349c1`.
- [Release notes](https://github.com/openthread/openthread/releases)
- [Commits](openthread/openthread@45c5fe4...f9349c1)

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

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