Bump third_party/openthread/repo from 0019f38 to 9f9d0a5

Bumps [third_party/openthread/repo](https://github.com/openthread/openthread) from `0019f38` to `9f9d0a5`.
- [Release notes](https://github.com/openthread/openthread/releases)
- [Commits](openthread/openthread@0019f38...9f9d0a5)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

third_party/openthread/repo

@@ -0,0 +1 @@
+9f9d0a5a33f2f5c4a45450ff5bfabfdfff7a197b