The refactor in f70fc980 solved an
inconsistency in `buildAndInstallUnpackedPackage`. Namely, before the
refactor, we didn't pass `hsSetupBuildArgs` to the build invocations,
and afterwards we did.

The result is that build targets of (legacy) package `B`, that a package
`A` depends on, are now passed to the ./Setup build invocation of
package `B` (e.g. `./Setup build lib:openapi3` rather than just `./Setup
build`).

This means we no longer /build always all targets of a legacy-package/
(for example, the lib, the testsuites and the executables).
Instead only the required target (just the lib) will be built.

However, despite now passing the build args to `./Setup build`, we
weren't passing the same arguments to the `./Setup copy` invocation.
Therefore, `./Setup copy` would also try to copy targets of the package
that weren't built, resulting in a failure.

This fixes that failure by correctly passing the build targets to the
`./Setup copy` invocation, just like we do for the `./Setup build` one.

Fixes #9640