Fix type annotation

app.py

@@ -70,7 +70,7 @@ def binarize_mask(mask: np.ndarray) -> np.ndarray:
     return mask
 
 
-def update_trimap(foreground_mask_editor: gr.ImageEditor, unknown_mask_editor: gr.ImageEditor) -> np.ndarray:
+def update_trimap(foreground_mask_editor: dict, unknown_mask_editor: dict) -> np.ndarray:
     foreground = foreground_mask_editor["layers"][0]
     foreground = binarize_mask(foreground)