Because the SmartThings IFT TT channel does not have a “inactive motion” trigger, you have to daisychain this.
Using official smartlighting feature and have the motion sensor being inactive turn off a virtual switch.
Then use that virtual switch turning off to be the IFTTT “if.” And use the lutron switch being set to 0 as the “that.”
If you haven’t used virtual switches before, here’s the FAQ for that:
Then once you have the switch set up, it will show up in any list of switches, including Smart lighting automation. So then you’d have a smart lighting automation that looks something like this
You should also set up an automation so that motion on the sensor turns the switch on in the first place. But you don’t need to set up an IFTTT recipe for that, just a smart lighting automation to get the switch ready