rm Amazon in-app purchase tracking

Amazon doesn't have an official API for SDKs to track IAP, as a result
we have been using reflection to hook into internal API's. This is
extremely fragile, it breaks on every patch version of Amazon's IAP
library.

Due to the fact the market is moving away IAP through app stores and
Amazon's pullback on bring the Amazon store to other platforms
(like Windows) the importance has shrunk so low the maintenance isn't
worth it anymore.

Author: jkasten2

OneSignalSDK/onesignal/core/src/main/java/com/onesignal/core/CoreModule.kt

@@ -29,7 +29,6 @@ import com.onesignal.core.internal.permissions.IRequestPermissionService
 import com.onesignal.core.internal.permissions.impl.RequestPermissionService
 import com.onesignal.core.internal.preferences.IPreferencesService
 import com.onesignal.core.internal.preferences.impl.PreferencesService
-import com.onesignal.core.internal.purchases.impl.TrackAmazonPurchase
 import com.onesignal.core.internal.purchases.impl.TrackGooglePurchase
 import com.onesignal.core.internal.startup.IStartableService
 import com.onesignal.core.internal.time.ITime
@@ -80,7 +79,6 @@ internal class CoreModule : IModule {
             .provides<IStartableService>()
 
         // Purchase Tracking
-        builder.register<TrackAmazonPurchase>().provides<IStartableService>()
         builder.register<TrackGooglePurchase>().provides<IStartableService>()
 
         // Register dummy services in the event they are not configured. These dummy services