tests: secure_storage: psa: its: add test scenarios for 64-bit UIDs

Add test scenarios for the newly-added CONFIG_SECURE_STORAGE_64_BIT_UID
enabled with both the ZMS and Settings backends.
They don't test backward compatibility but it makes sure that secure
storage compiles and works fine with this configuration.

Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>