Don't check api.json files into git (#3565)

These were needed when the docs lived in a different repo, but they
don't any more so we can get rid of them.

### Change Type
- [x] `internal` — Does not affect user-facing stuff
- [x] `chore` — Updating dependencies, other boring stuff

scripts/vercel/build-docs.sh

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 set -eux
 
+yarn run -T lazy build-api
 yarn run -T lazy refresh-everything  --filter=apps/docs
 yarn run -T lazy build --filter=apps/docs