Test interoperability of icmsg with old implementation.#3

doki-nordic merged 2 commits intoicmsg-1.1-ncsdoki-nordic/sdk-zephyr:icmsg-1.1-ncsfrom

icmsg-1.1-ncs-interop-testdoki-nordic/sdk-zephyr:icmsg-1.1-ncs-interop-testCopy head branch name to clipboard