tests: bluetooth: tester: Fix invalid checks in oob_data_request

CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY disables all but legacy OOB
pairing (including LE SC) and is not intended for enabling/disabling
support for legacy OOB pairing. bt_le_oob_set_legacy_tk() depends on
CONFIG_BT_SMP_SC_PAIR_ONLY so just use same check here.

For BT_CONN_OOB_LE_SC only supported way to disable LE SC OOB is
to force BT_SMP_OOB_LEGACY_PAIR_ONLY which disables all pairing
except legacy OOB support.

Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>