Fix type annotation

app.py

@@ -73,7 +73,7 @@ class App:
     @torch.inference_mode()
     def generate_interpolated_images(
             self, seed0: int, psi0: float, seed1: int, psi1: float,
-            num_intermediate: int) -> tuple[list[np.ndarray], np.ndarray]:
+            num_intermediate: int) -> list[np.ndarray]:
         seed0 = int(np.clip(seed0, 0, np.iinfo(np.uint32).max))
         seed1 = int(np.clip(seed1, 0, np.iinfo(np.uint32).max))