native_window_aidl: include cpp headers only when needed

native_window_aidl.h only enables the AIDL glue for CPP/NDK backends,
so the headers required for AIDL glue should only be included
for CPP/NDK backends.

This CL includes headers required by AIDL glue only when the AIDL
glue is actually being enabled.

Bug: 283283111
Test: Verified that Surface can be used in an AIDL file.
Change-Id: I1945d3cfc247bfa507ca4fef03044e1078e598f0