refs https://github.com/TryGhost/Product/issues/3832
- Fixed portal preview when no tiers are enabled
- Fixed portal preview not respecting access setting
- Disabled portal customisation when nobody can sign up
- Fixed custom theme settings not updated when theme is changed
- Added publication icon setting in newsletters
- Added extremely rudimentary editor role display
- Fixed drag overlay position in modals
refs https://github.com/TryGhost/Product/issues/3676
- add filter for sidebar display of theme errors (angry red box)
- filter specific to each page feature, will need to add each one by this approach
refs https://github.com/TryGhost/Team/issues/3349
Tidies up the remaining major pieces which were not covered by tests.
Extends the existing test patterns, although the API mocks are getting a
bit unmanageable.
