fix: vae sampling mode

Author: tolgacangoz

src/diffusers/pipelines/wan/pipeline_wan_video2video.py

@@ -419,12 +419,7 @@ def prepare_latents(
         )
 
         if latents is None:
-            if isinstance(generator, list):
-                init_latents = [
-                    retrieve_latents(self.vae.encode(video[i].unsqueeze(0)), generator[i]) for i in range(batch_size)
-                ]
-            else:
-                init_latents = [retrieve_latents(self.vae.encode(vid.unsqueeze(0)), generator) for vid in video]
+            init_latents = [retrieve_latents(self.vae.encode(vid.unsqueeze(0)), sample_mode="argmax") for vid in video]
 
             init_latents = torch.cat(init_latents, dim=0).to(dtype)