Tunnel destruction icon persists forever

If you start destroying a tunnel that is already being destroyed by someone else, once it finishes the icon in the middle of your screen will stay there after the tunnel is destroyed.

Steps to reproduce:

1. Build a tunnel
2. Have one person start destroying it
3. Start destroying it while the other person is destroying it
4. Notice that the tunnel destruction icon stays on your screen after it is destroyed

Expected results:

Icon disappears after tunnel is destroyed.

Tunnel destruction icon persists forever