Set input coords to invalid if mouse off-screen (#30164)

This may be a breaking change for some stuff, I only tested basic combat stuff + throwing.

This fixes the coordinates setting an off-screen position to the top-left pixel and blocks throw attempts as a result.

Content.Server/Hands/Systems/HandsSystem.cs

@@ -170,7 +170,7 @@ namespace Content.Server.Hands.Systems
 
         private bool HandleThrowItem(ICommonSession? playerSession, EntityCoordinates coordinates, EntityUid entity)
         {
-            if (playerSession?.AttachedEntity is not {Valid: true} player || !Exists(player))
+            if (playerSession?.AttachedEntity is not {Valid: true} player || !Exists(player) || !coordinates.IsValid(EntityManager))
                 return false;
 
             return ThrowHeldItem(player, coordinates);