submodule: bump third_party/openthread/repo from b92bd46 to `c2d526…

…5` (#2639)

Bumps [third_party/openthread/repo](https://github.com/openthread/openthread) from `b92bd46` to `c2d5265`.
- [Commits](openthread/openthread@b92bd46...c2d5265)

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

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