submodule: bump openthread from a49c1f5 to 1b80561 (#1134)

Bumps [openthread](https://github.com/openthread/openthread) from `a49c1f5` to `1b80561`.
- [Commits](openthread/openthread@a49c1f5...1b80561)

---
updated-dependencies:
- dependency-name: openthread
  dependency-version: 1b805618025e406f85227187e3f2bc0b73fa17bd
  dependency-type: direct:production
...

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Author: dependabot[bot]