submodule: bump openthread from e029417 to 49c59ec

Bumps [openthread](https://github.com/openthread/openthread) from `e029417` to `49c59ec`.
- [Release notes](https://github.com/openthread/openthread/releases)
- [Commits](openthread/openthread@e029417...49c59ec)

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

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