We now create npm packages to cover all the public api assertions in tools/public_api_guard.
We no longer depend on ts-api-guardian from npm - it is now stale since the repository was archived.
There is no longer a gulp task to enforce or accept the public API, this is in CircleCI as part of running all bazel test targets.
PR Close#22639
(Coincidentally), this wasn't an issue before fdfeaaf1f, because
pre-verification was run after `test.sh`, during which `aio-builds-setup` was
built.
Now that `deploy-staging.sh` is being run before `test.sh`, we need to build
the `aio-builds-setup` scripts first.