Remove unused usings

PartyModes/PartyModeChallenge/CPartyScreenChallengeNames.cs

@@ -17,10 +17,7 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Windows.Forms;
 using VocaluxeLib.Menu;
-using VocaluxeLib.Profile;
 
 namespace VocaluxeLib.PartyModes.Challenge
 {