Update public Android OneSignal module references

OneSignal-Android-SDK made a breaking change at some point to public BuildConfig classes.
The OneSignal native SDK removed the BuildConfig classes in the modules.
Replaced it with other public classes to meet the requirements notes above them.

Author: jkasten2

OneSignalSDK.DotNet.Android/AndroidOneSignal.cs

@@ -16,13 +16,14 @@ namespace OneSignalSDK.DotNet.Android;
 
 public class AndroidOneSignal : IOneSignal
 {
-   /** These static references are not used, but we need to reference at least one class
-    *  in the binding projects that are otherwised not referenced. If we did *not*, then
-    *  the binding DLLs will not be included in the output bin directory.
-    */
-    private static Com.OneSignal.Android.InAppMessages.BuildConfig InAppMessagesBuildConfig;
-    private static Com.OneSignal.Android.Notifications.BuildConfig NotificationsBuildConfig;
-    private static Com.OneSignal.Android.Location.BuildConfig LocationBuildConfig;
+    /** These static references are not used, but we need to reference at least one class
+     *  in the binding projects that are otherwised not referenced. If we did *not*, then
+     *  the binding DLLs will not be included in the output bin directory.
+     */
+    
+    private static Com.OneSignal.Android.InAppMessages.IInAppMessagesManager InAppMessagesBuildConfig;
+    private static Com.OneSignal.Android.Notifications.INotificationsManager NotificationsBuildConfig;
+    private static Com.OneSignal.Android.Location.ILocationManager LocationBuildConfig;
 
     public IUserManager User { get; } = new AndroidUserManager();