Clean up follow implementation; stop following when leader leaves the scene

front/src/Phaser/Game/GameScene.ts

@@ -1715,6 +1715,10 @@ ${escapedMessage}
         });
     }
 
+    public findPlayer(testFunction: (player: RemotePlayer) => boolean): RemotePlayer | undefined {
+        return Array.from(this.MapPlayersByKey.values()).find(testFunction);
+    }
+
     /**
      * Called by the connexion when a new player arrives on a map
      */