Workflow: enable AES256 image encryption tests
Workflow: enable AES256 image encryption tests

Signed-off-by: Salome Thirot <7625c0250cd1829333b6cb32d834782a8c70481e@arm.com>

runtimeco/mcuboot,ATmobica/mcuboot,runtimeco/mcuboot,runtimeco/mcuboot,ATmobica/mcuboot,ATmobica/mcuboot,ATmobica/mcuboot,runtimeco/mcuboot,runtimeco/mcuboot,ATmobica/mcuboot