submodule: bump third_party/openthread/repo from 2868c9c to `a0f861…
#6071
| Job | Run time |
|---|---|
| 7m 17s | |
| 7m 17s |
2868c9c to `a0f861…
#6071
| Job | Run time |
|---|---|
| 7m 17s | |
| 7m 17s |