This commit upgrades all dependencies in `scripts-js/` to latest versions and also includes all necessary code changes to ensure the tests are passing with the new dependency versions. PR Close #36837
Related discussion: https://github.com/angular/angular/pull/23576#discussion_r187925949. PR Close #25671
The server no longer has files uploaded to it. Instead it is more accurate to refer to it as dealing with "previews" of PRs.