Fix copying subabilities to no longer duplicate them (#11399)

* Fix Subability copy bug (fix #10526 )

* Cards which copy abilities of other cards should not copy subabilities.

* Enable previously-failing tests

* Find more addAbility that should be done without subabilities

* Add documentation to addAbility function

* Add warning about not using basic addAbility when copying from a source

* Invert withSubabilities to fromExistingObject

Mage/src/main/java/mage/abilities/Ability.java

@@ -332,6 +332,8 @@ public interface Ability extends Controllable, Serializable {
 
     /**
      * Gets the list of sub-abilities associated with this ability.
+     * When copying, subabilities are copied separately and thus the list is desynced.
+     * Do not interact with the subabilities list during a game!
      *
      * @return
      */