submodule: bump third_party/openthread/repo from `8987ae4` to `f7802d6` (#785)
submodule: bump third_party/openthread/repo from `8987ae4` to `f7802d6` (#785)

Bumps [third_party/openthread/repo](https://github.com/openthread/openthread) from `8987ae4` to `f7802d6`.
- [Commits](https://github.com/openthread/openthread/compare/8987ae4c218140ab49774f734efe449572bb0f60...f7802d60a17a355bbfd02f25a34035bddf5ee333)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
openthread/borderrouter,openthread/ot-br-posix,openthread/ot-br-posix,openthread/borderrouter,openthread/ot-br-posix,openthread/ot-br-posix,openthread/borderrouter,openthread/borderrouter,openthread/borderrouter,openthread/ot-br-posix,openthread/ot-br-posix,openthread/borderrouter