refs https://github.com/TryGhost/Team/issues/1528
- adds "opt-in existing" toggle to newsletter modal that's only shown when creating a newsletter
- defaults to true
- updated newsletter save flow to show confirmation before creation
- alters message to reflect auto-subscribe selection
- count of existing subscribed members is not implemented as it's not yet supported by the API
- updated newsletter adapter and save flow to use auto opt-in selection
- when option is checked the save URL is changed to `POST /members/?opt_in_existing=true`
- modified task button component to ignore a task return value of `canceled` so when it's received the buttons returns to the idle state instead of showing a saved or failed state
- used by save routine when the "Back to edit" button is clicked in the create confirmation modal
refs https://github.com/TryGhost/Ghost/pull/14491
- API endpoint used when completing verification of a newsletter email change has moved to `PUT /newsletters/verifications/` to follow our API patterns
refs https://github.com/TryGhost/Team/issues/584
refs https://github.com/TryGhost/Team/issues/1498
- updated newsletter save routine in `edit-newsletter` modal to open an email confirmation modal if the API indicates one was sent
- modal indicates that the previously set or default email will continue to be used until verified
- response from API when saving looks like `{newsletters: [{...}], meta: {sent_email_verification: ['sender_name]}}`
- added custom newsletter serializer and updated model so that the `meta` property returned in the response when saving posts is exposed
- Ember Data only exposes meta on array-response find/query methods
- https://github.com/emberjs/data/issues/2905
- added `/settings/members-email-labs/?verifyEmail=xyz` query param handling
- opens email verification modal if param is set and instantly clears the query param to avoid problems with sticky params
- when the modal opens it makes a `PUT /newsletters/verify-email/` request with the token in the body params, on the API side this works the same as a newsletter update request returning the fully updated newsletter record which is then pushed into the store
- removed unused from/reply address code from `<Settings::MembersEmailLabs>` component and controller
- setting the values now handled per-newsletter in the edit-newsletter modal
- verifying email change is handled in the members-email-labs controller
- fixed mirage not outputting pluralized root for "singular" endpoints such as POST/PUT requests to better match our API behaviour
refs https://github.com/TryGhost/Team/issues/1441
- switched "leave settings" confirmation modal on members email settings screen over to modern modal pattern
- removed unused `showEmailDesignSettings` property and `closeEmailDesignSettings()` action on `<Settings::MembersEmailLabs>` component
- the used property and action live on the controller, looks like it was a copy/paste hangover when functionality was moved to a component
- added newsletter model
- includes design-related attributes which are not yet supported by the API but are due to be added
- includes `default` attribute but there is no setting for it, due to be removed from the API but it's needed for save not to error for now
- set up basic mirage model and endpoints
- added validation for main settings to match API validation
- added `EditNewsletter` modal
- separate tabs for general newsletter settings and design-related settings
- used for both creating and editing newsletters
- added `/settings/members-email/newsletters/new` and `/settings/members-email/newsletters/:id` routes
- both display the `EditNewsletter` modal on top of the members-email settings screen with the appropriate newsletter model
- updated `<Settings::MembersEmailLabs::NewsletterManagement>` component to work with real newsletter model instances and the new add/edit routes
- removed now-unused `newsletter` service that was providing mocked data for earlier design iteration
