tests: drivers: mbox: Add negative tests for MBOX driver

Add negative test cases for the MBOX driver.
Confirm that driver implementation is aligned with
the MBOX API documentation available at
https://docs.zephyrproject.org/latest/hardware/peripherals/mbox.html



Enable test execution on nRF54H20 Application and PPR cores.

Signed-off-by: Sebastian Głąb <sebastian.glab@nordicsemi.no>