Update desktop.json (#664)

No quantization until we move the PyTorch pin to include the new MPS quantized kernels

Author: mikekgfb

config/data/desktop.json

@@ -1,4 +1,4 @@
 {
     "executor": {"accelerator": "fast"},
-    "precision": {"dtype" : "fast16"},
+    "precision": {"dtype" : "fast16"}
 }