fix many type hint errors

Author: DefTruth

src/diffusers/models/transformers/transformer_hunyuan_video.py

@@ -1038,7 +1038,7 @@ def forward(
         guidance: torch.Tensor = None,
         attention_kwargs: Optional[Dict[str, Any]] = None,
         return_dict: bool = True,
-    ) -> Union[torch.Tensor, Transformer2DModelOutput]:
+    ) -> Union[Tuple[torch.Tensor], Transformer2DModelOutput]:
         if attention_kwargs is not None:
             attention_kwargs = attention_kwargs.copy()
             lora_scale = attention_kwargs.pop("scale", 1.0)