Remove duplicate code for X costs (#12551)

* Replace "([a-zA-Z]+).getManaCostsToPay().getX()" with CardUtil.getSourceCostsTag(game, $1, "X", 0)
Fix Disrupting Shoal

* Change final card .getX() calls

* Condense all ManacostVariableValue enum values into "instance"

* Further removal of getX, Display X symbol for non-mana X cards

* Fix test

* Fully remove ManaCosts.getX

* Replace all different X dynamic values with GetXValue

* Remove individual cards checking getAmount for X values (leaving cost reduction that does not use X)

* Add null check for game object inside getSourceCostsTagsMap

* fix build errors

* fix Vicious Betrayal

* text fix

Mage/src/main/java/mage/util/CardUtil.java

@@ -1737,6 +1737,9 @@ public final class CardUtil {
      */
     public static Map<String, Object> getSourceCostsTagsMap(Game game, Ability source) {
         Map<String, Object> costTags;
+        if (game == null) {
+            return null;
+        }
 
         // from spell ability - direct access
         costTags = source.getCostsTagMap();