Core/Player: Allow companion action buttons to be saved

Port From (https://github.com/TrinityCore/TrinityCore/commit/e15898bf560fc8159777a2a29a29d6a91ffdb590)

Source/Framework/Constants/PlayerConst.cs

@@ -330,6 +330,7 @@ namespace Framework.Constants
         Dropdown = 0x30,
         Macro = 0x40,
         CMacro = C | Macro,
+        Companion = 0x50,
         Mount = 0x60,
         Item = 0x80
     }

Source/Game/Entities/Player/Player.cs

@@ -1363,6 +1363,15 @@ namespace Game.Entities
                         return false;
                     }
                     break;
+                case ActionButtonType.Companion:
+                {
+                    if (GetSession().GetBattlePetMgr().GetPet(ObjectGuid.Create(HighGuid.BattlePet, action)) == null)
+                    {
+                        Log.outError(LogFilter.Player, $"Player::IsActionButtonDataValid: Companion action {action} not added into button {button} for player {GetName()} ({GetGUID()}): companion does not exist");
+                        return false;
+                    }
+                    break;
+                }
                 case ActionButtonType.Mount:
                     var mount = CliDB.MountStorage.LookupByKey(action);
                     if (mount == null)