GS would never do it.
They really shouldn't. First off, they will just laugh at this offer. But even if the Celtics present a better offer, the Warriors would be dumb to trade Draymond right now.
If I'm the Warriors, I would let them hash it out during the year, and if KD leaves, so be it. The Warriors would still be contenders without Durant. Steph Curry would still be a top 5 player, they would still attract Free Agents to help out, and they would still be really good. I'm not risking trading Draymond only for KD to still be able leave after the fact.
Also, you can trade Draymond next year if need be, if Durant is the choice to keep. It doesn't have to be this year, as Green will still be under contract. If it came down to moving Dray to resign Durant, then trade him next summer.
I'm not moving Draymond this year, it would be stupid to do so. Win the championship this year. Cement your legacy as a true dynasty, worry about it next summer.