Stub/Impl selection for sdk variants

If a dependency has ndk stubs, then the sdk variant of the library
should link against the ndk stub variant and not the impl/apex_stubs variant

Unlike module-libapi, the depdendency does not go through an
@api_surfaces external repo indirection. This indirection was created to
support Multi-tree, and will likely  be removed in the future

Test: Added a unit test
Bug: 298085502
Change-Id: Ie081e153fa586b6c22db0b8e42f91149fd8e5d9b