refactor(plugin): let currentColor throw a more verbose error

Originally, accessing currentColor / -Team / -Player resulted in a
non-descriptive IndexOutOfBoundsException for accessing index 0 of an
empty list (which previously held all currently active colors)

Now it throws a GameLogicException with a short explanation

Author: anarchuser

plugin/src/shared/sc/plugin2021/GameState.kt

@@ -48,7 +48,11 @@ class GameState @JvmOverloads constructor(
     private var currentColorIndex: Int = 0
 
     val currentColor: Color
-        get() = orderedColors[currentColorIndex]
+        get() = try {
+            orderedColors[currentColorIndex]
+        } catch (e: IndexOutOfBoundsException) {
+            throw GameLogicException("Trying to access the currently active color after the game has ended")
+        }
 
     @XStreamAsAttribute
     override var turn: Int = 0