tests: ztest base: fix board name

Use full board name in cmake file.
Akin to the fix done in #80270
https://github.com/zephyrproject-rtos/zephyr/pull/80270/
following the changes from
https://github.com/zephyrproject-rtos/zephyr/pull/77250/
In which twister now uses the full board name when calling cmake.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
1 file changed