Convert sigmas to np.array in FlowMatch set_timesteps

Author: hlky

src/diffusers/schedulers/scheduling_flow_match_euler_discrete.py

@@ -207,6 +207,7 @@ def set_timesteps(
 
             sigmas = timesteps / self.config.num_train_timesteps
         else:
+            sigmas = np.array(sigmas).astype(np.float32)
             num_inference_steps = len(sigmas)
         self.num_inference_steps = num_inference_steps