Stop the panel flicker on videos that play

PROBLEM
- The panel flashed repeatedly on videos that play.
- Each flash started a lookup for a video that played correctly.
- The add-on made a new decision for each change in the player area.
- The add-on sent many requests to the archives.

FIX
- The add-on makes one decision for each video.
- After the decision, the add-on stays idle.
- The add-on does not look at a video that plays.

HOW
1. Find the error box with the CSS display value. Do not use the size of the box.
2. If the box is hidden, stop. Do not start a lookup.
3. Keep the video ID after the decision "no panel". Do not decide again for the same ID.