fix compare_videos in vlc.py (#242)

fix result in the same format of float number.

desktop_env/evaluators/metrics/vlc.py

@@ -308,7 +308,7 @@ def compare_videos(video_path1, video_path2, max_frames_to_check=100, threshold=
 
         # If a video ends, then check if both ended to confirm they are of the same length
         if not ret1 or not ret2:
-            return ret1 == ret2
+            return 1. if ret1 == ret2 else 0. # return float only 
 
         # Convert frames to PIL Images
         frame1 = Image.fromarray(cv2.cvtColor(frame1, cv2.COLOR_BGR2RGB))