[ExternalGenericMetadataBuilder] Fix install invocation. Add dependency. (#71872)
The call `swift_install_in_component` does not support multiple
component depending on the `TARGET` pieces, so providing it several
times is only confusing for humans. Deduplicate the repeated component
and move it outside of the `ARCHIVE` and `LIBRARY` pieces.
Additionally, `add_swift_host_library` does not provide
a `INSTALL_IN_COMPONENT` like `add_swift_target_library` does, so there
is a missing dependency between the `compiler` component and the
library. This is not a problem with `build-script` because the target is
part of `all`, but it is a problem when using `ninja compiler`, for
example.`