Import AttentionMixin in transformer_wan_vace.py

Special thanks to @tolgacangoz 🙇‍♂️

Author: J4BEZ

src/diffusers/models/transformers/transformer_wan_vace.py

@@ -21,7 +21,7 @@
 from ...configuration_utils import ConfigMixin, register_to_config
 from ...loaders import FromOriginalModelMixin, PeftAdapterMixin
 from ...utils import USE_PEFT_BACKEND, logging, scale_lora_layers, unscale_lora_layers
-from ..attention import FeedForward
+from ..attention import AttentionMixin, FeedForward
 from ..cache_utils import CacheMixin
 from ..modeling_outputs import Transformer2DModelOutput
 from ..modeling_utils import ModelMixin