test uses a deprecated package (js)

[paul-charlton]

When running flutter pub outdated it's reporting a usage of a transitive dependency on js:

js
Package js has been discontinued. See https://dart.dev/go/package-discontinue

flutter pub deps then reports that the dependency is from test (https://github.com/dart-lang/test/blob/master/pkgs/test/pubspec.yaml#L20).

In the discontinue notes, they suggest using dart:js_interop.

[jakemac53]

I believe this was recently addressed in #2478

[jakemac53]

cc @natebosch idk if we want to publish that, we have gotten several reports from users so it would at least stop confusing people, even if there isn't immediate value to actually releasing.