Core/Conditions: Refactor ConditionMgr internals to get rid of separate containers for some condition source types

Port From (https://github.com/TrinityCore/TrinityCore/commit/0b5406dd882c6d96bc1be6fd0a78375c3b316415)

Source/Game/Entities/Creature/Gossip.cs

@@ -789,7 +789,7 @@ namespace Game.Misc
         public uint BoxBroadcastTextId;
         public int? SpellID;
         public int? OverrideIconID;
-        public List<Condition> Conditions = new();
+        public ConditionsReference Conditions;
     }
 
     public class GossipMenuAddon
@@ -817,6 +817,6 @@ namespace Game.Misc
     {
         public uint MenuId;
         public uint TextId;
-        public List<Condition> Conditions = new();
+        public ConditionsReference Conditions;
     }
 }