Can only sign up with a free plan

[charlag]

Test notes

• [x] Singup on web - all plans
• [x] Signup on iOS w/o usage test - free
• [x] Signup on iOS w/ usage test - paid plans
• [x] Upgrade on iOS (e.g. adding calendar), w/o usage test - not available
• [x] Upgrade on iOS (e.g. adding calendar), w/ usage test - paid plans

[paw-hub]

Downgrading to Free and then trying to switch back to Revolutionary results in bad request error when communicating with SwitchAccountTypeService with the server log "Can't use this method to change subscriptions if AppStore - please configure your subscription from within the App Store instead!"

At first, there was no native dialogue. If I restart the app, a native dialog appears, but it still errors upon signing up for the plan, and I am still left on the free plan with no way to change it anymore through the app.