irq: multilevel: compile 3rd level IRQ APIs only when enabled

This revert the idea of 3fa7d783 from #78845.

The 3rd level IRQ APIs won't compile when
CONFIG_3RD_LEVEL_INTERRUPT_BITS=0.

Updated testcase accordingly.

Signed-off-by: Yong Cong Sin <ycsin@meta.com>
Signed-off-by: Yong Cong Sin <yongcong.sin@gmail.com>

Signed-off-by: Yong Cong Sin <yongcong.sin@gmail.com>