### Changes:
- `InternalAPI` is now `Sendable` to deal with new compilation error
- `PaywallEventStoreType` is now `Sendable`
- Extracted `SK2BeginRefundRequestHelperType` to make
`SK2BeginRefundRequestHelper` `Sendable`
- Updated `MockSK2BeginRefundRequestHelper` to be thread-safe and
`Sendable`
- Fixed compilation error in `DebugContentViews`
- Fixed compilation error in `DebugViewModel`
- Fixed compilation error in `StoreMessagesHelper`
### Description
StoreKit displays different types of in-app messages on app launch, but
it provides an API to disable that and show these messages at a
different time. This PR wraps those APIs to make them easier to use
through our SDK.
#### New APIs
- Add new configuration parameter to defer StoreKit's automatic in-app
messages
- Add new method in `Purchases` to display a list of specific message
types
- New `StoreKitMessageType` enum mapping to the types used by StoreKit
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Co-authored-by: NachoSoto <NachoSoto@users.noreply.github.com>
Will Taylor