This is an improvement over directly referencing the prebuilt because
bp2build can now emit BUILD files that contain a dep to
//build/soong/zip/cmd:soong_zip even though we're not converting the
soong_zip module.
It helps to make progress despite not having go rules support to
convert/build soong_zip. This unblocks many modules, like genrules and
gensrcs that use soong_zip in tools. soong_zip doesn't change often, so
it's not risky to depend on the prebuilt instead of source version.
Bug: 194644518
Bug: 248222296
Test: bp2build CI
Change-Id: Idef0c27ec0fb43a9097d750ec72fba00644c9f2a
