Modify VLC launch command and fullscreen detection

- Add VLC_VERBOSE=-1 to suppress verbose logging in VLC launch commands across multiple example files
- Update is_vlc_fullscreen function to handle cases where screen size or window size is None
- Improve robustness of VLC-related metrics and example configurations

evaluation_examples/examples/vlc/aa4b5023-aef6-4ed9-bdc9-705f59ab9ad6.json

@@ -17,9 +17,9 @@
     },
     {
       "type": "launch",
-        "parameters": {
-            "command": ["vlc", "/home/user/Desktop/flipped_1984_Apple_Macintosh_Commercial.mp4"]
-        }
+      "parameters": {
+        "command": ["VLC_VERBOSE=-1", "vlc", "/home/user/Desktop/flipped_1984_Apple_Macintosh_Commercial.mp4"]
+      }
     },
     {
       "type": "execute",