Fix default piece in Shogi promotions

Fix default piece in Shogi promotions

In Shogi the default should be promotion, but it was using Queen like
the other variants. As the +/= issue was decided based on comparing this
default promotion piece with the moved piece, the Lance (which internally
is represented by Queen) would by default defer. Now the up-click of
a drag-drop move (which would bypass sweep selection) sets the default
choice to the promoted partner if the pieceToCharTable specifies one.