CPS: Support exporting "link dependent libraries".

Teach CPS export to fill the `dyld_requires` attribute based on the
equivalent of the `IMPORTED_LINK_DEPENDENT_LIBRARIES` CMake property.
(Note that, in practice, I don't believe this can ever contain
non-targets, and CPS does not anyway support the `dyld_libraries`
attribute that those would require at this time.

Issue: #27501