refactor(typescript): migrate BaseAuthenticator and OAuthPasswordGrant

[BobrImperator]

• Refactors BaseAuthenticator and OAuth2PasswordGrantAuthenticator to typescript
• Adds typed-event-target as devDependency to allow typing CustomEvents emmited by authenticators.
• Removes a bunch of isEmpty calls from the authenticators and relies on native mechanisms instead.
• Deprecates responseText and responseJSON returned by the OAuth2PasswordGrantAuthenticator.
• Bumps torii deprecation to 8.0.0

[github-actions]

Some tests with 'continue-on-error: true' have failed:

• classic-test-app test:one ember-beta

• test-app test:one ember-beta

• classic-test-app test:one ember-canary

• test-app test:one ember-canary

  Created by continue-on-error-comment

[BoussonKarel]

What are the alternatives for reponseJSON and reponseText? I use these to show the error returned by the backend on login and since the response you return has already been read, it's not an option to use that one.\

Is there any chance you could return a copy of the response (before it was read)? (or copy the response, read that one and send the original)

[BobrImperator]

Hi @BoussonKarel. As you've noticed, there's no clear migration path from these properties which was an oversight.
I've taken a look and made an issue along with a draft PR that implements your suggestion see issue and a PR.

I'm not sure if this is the way forward however, I should be able to take a better look later this week to align the password authenticator with other authenticators instead in backwards compatible way.