TTSD-20438

Rebar marks: Previously, when XS_ENABLE_REBAR_MARK_LEADER_LINE_BASE_POINT_OPTIMIZATION was set to TRUE, any rebar mark leader line associativity points could be moved. Now the optimization is only applied to the marks that have the Placing method value Free. In practice, this prevents the optimization from moving manually moved marks, because moving a mark manually changes the value of its Placing method to Fixed.