Re-enable the Prettier eslint plugin

[mansona]

I don't know why this was disabled 🤔 I've just re-enabled it and then ran lint-to-the-future ignore to not change every line in the repo all at once 😂

[github-actions[bot]]

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

• ember-beta

  • ember-canary
  • ember-release
  • embroider-optimized
  • embroider-safe

  Created by continue-on-error-comment