fix: align sigmas device in UniPCMultistepScheduler.set_timesteps

Author: conanna

src/diffusers/schedulers/scheduling_unipc_multistep.py

@@ -478,7 +478,8 @@ def set_timesteps(
         # add an index counter for schedulers that allow duplicated timesteps
         self._step_index = None
         self._begin_index = None
-        self.sigmas = self.sigmas.to("cpu")  # to avoid too much CPU/GPU communication
+        # self.sigmas = self.sigmas.to("cpu")  # to avoid too much CPU/GPU communication
+        self.sigmas = self.sigmas.to(device=device)
 
     # Copied from diffusers.schedulers.scheduling_flow_match_euler_discrete.FlowMatchEulerDiscreteScheduler.time_shift
     def time_shift(self, mu: float, sigma: float, t: torch.Tensor):