Crane is still in need of supplies.
If this imperial decree means the Lion-Crane conflict ends, then they will either push their claim to Yasuki-lands (which would require some cost/gain analysis), or use their diplomatic support as a bargaining chip to get supplies (which is very much their MO). And who is in most need of support in Rokugans courts if not Unicorn?
Not saying it is a immediate match. Crane could very much try to put their support behind Lion or any other clan, but Unicorns need for diplomatic allies and Cranes need for supplies would align.