Class enum instead of hardcoded ints.

Removed superfluous .Valid() checks.

Check for spectator spawnrequest in case they somehow has a class, so we don't get "x players were supposed to be spawned but failed" if it happens.

include/Game/Systems/PlayerSpawnSystem.h

@@ -15,11 +15,19 @@ public:
     virtual void Update(double dt) override;
 
 private:
+    // This enum must correspond to the command values for PickTeam buttons.
+    enum class PlayerClass
+    {
+        None = 0,
+        Assault,
+        Defender,
+        Sniper
+    };
     struct SpawnRequest
     {
         int PlayerID;
         ComponentInfo::EnumType Team;
-        ComponentInfo::EnumType Class;
+        PlayerClass Class;
     };
 
     bool m_NetworkEnabled = false;