submodule: bump openthread from 4e52d85 to a363396 (#606)

Bumps [openthread](https://github.com/openthread/openthread) from `4e52d85` to `a363396`.
- [Commits](openthread/openthread@4e52d85...a363396)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>