- Removed the unused `appID` property from `GACAppCheckAPIService`.
- Removed heartbeat logging tests from `GACAppCheckAPIServiceTests`.
- Added request hook, additional headers and API key tests to `GACAppCheckAPIServiceTests`.
Publicly exposed the initWithApp:appCheckProvider: constructor in GACAppCheck for the non-Firebase-specific App Check SDK. Since an AppCheckProvider is explicitly specified when constructing this generic App Check SDK, the AppCheckProviderFactory protocol / pattern / functionality is no longer used.
Added a podspec for AppCheckInterop and added it as a dependency in the existing AppCheck podspec. This is a lightweight, protocol-only, dependency that non-Firebase SDKs can make use of.
Added logging macros as drop-in replacements for the GAC/FIRAppCheckLogger macros. These are simple wrappers around NSLog and are not compiled out based on the desired logging level.