tests: use CONFIG_ZTEST_NEW_API=y for bluetooth/controller/ctrl_cte_req

The bluetooth/controller/ctrl_cte_req wrongly defaulted to old Ztest API
after the introduction of the new unit_testing board.

Enforce use of CONFIG_ZTEST_NEW_API to get test working again.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>