fix get open orders cli_wallet command
Get open_order failed because the render function had a bug with the asset type:
get_open_orders howo
7 bad_cast_exception: Bad Cast
Invalid cast from object_type to string
{"type":"object_type"}
variant.cpp:478 as_string
Also the output did not have a working price
So this also fixes it while introducing new functional tests to make sure we catch those in the future.