cmake/rgw: add missing dependency on Arrow::Arrow

cmake/rgw: add missing dependency on Arrow::Arrow

when WITH_SYSTEM_ARROW is disabled, BuildArrow.cmake creates an
Arrow::Parquet target that depends on Arrow::Arrow:

  target_link_libraries(Arrow::Parquet INTERFACE Arrow::Arrow)

but when WITH_SYSTEM_ARROW is enabled, the targets we get from
find_package() do not carry this dependency. so rgw's cmake needs to
depend on both targets

Fixes: https://tracker.ceph.com/issues/55420
Signed-off-by: Casey Bodley <cbodley@redhat.com>
(cherry picked from commit 3f12d21418963f2a33b124185a2842a9c39e9cfa)