Core/Player: Delay the visibility update when setting the group to prevent crashing when a player enters the world in a group/raid.

Closes issue 4762

--HG--
branch : trunk

src/server/game/Entities/Player/Player.cpp

@@ -20851,7 +20851,7 @@ void Player::SetGroup(Group *group, int8 subgroup)
         m_group.setSubGroup((uint8)subgroup);
     }
 
-    UpdateObjectVisibility();
+    UpdateObjectVisibility(false);
 }
 
 void Player::SendInitialPacketsBeforeAddToMap()