`PaywallView` and `PaywallViewController` (along with the extensions)
still require iOS 16, but this paves the way to support iOS 15 down the
road if we need to.
### Main Changes:
- Changed all `@available` annotations
- Added CI tests
- Replaced `ViewThatFits` with the "biggest" version
- Because of that, `scrollableIfNeeded` is always scrollable
- Double `Regex` implementation (keeping the modern one), so once we
drop support for iOS 15 we can just keep the modern one.
### TODO:
- [x] Add snapshots
- [x] Test paywalls
- [x] Updated APITester to verify this
This was broken in #2923. Unfortunately it couldn't be caught by
snapshot tests because those don't display progress views.
I simplified `PackageButtonStyle` to get the shared
`PurchaseHandler.actionInProgress` state instead of relying on whether
the button is enabled.
This allows `PaywallView` to handle state handling during a purchase:
instead of the previous behavior where only `PurchaseButton` would
disable itself, now the entire `PaywallView` is disabled.
I extracted `PackageButtonStyle` so any template with multi-package
selection can get this same behavior: the package selection also becomes
disabled, as well as any other button (like restore purchases).
I've also cleaned up the templates since we no longer needed the
"Content" inside view, and they can be simplified with a single type.
By making `PurchaseHandler` `@MainActor` we also ensure that all these
state transitions lead to UI changes happening exclusively on the main
thread.
