refs: https://github.com/TryGhost/Toolbox/issues/245
- sendTestEmail was missing a serializer because it's deliberately a passthrough
- With the upcoming refactor we want to have all the serializers defined explicitly
- This will allow us to change the default behaviour
- Updated the tests to prove the body doesn't change
refs https://github.com/TryGhost/Toolbox/issues/135
- Going though local utils allows to have the "withFrontend: false" flag applied only to the e2e-api test suites. This way we can gradually introduce the no-frontend change across all test suites