Fixed static values getting into release .aar file

Author: jkasten2

OneSignalSDK/onesignal/build.gradle

@@ -3,9 +3,13 @@ apply plugin: 'com.android.library'
 android {
     compileSdkVersion 28
     defaultConfig {
-        manifestPlaceholders = [onesignal_app_id: 'b2f7f966-d8cc-11e4-bed1-df8f05be55ba',
+        // Normally we shouldn't need to redefine manifestPlaceholders for our onesignal project
+        //   but Android Studio gets a sync error if these are not here.
+        //      - /gradlew onesignal:assembleRelease is fine from the console.
+        // We can't use static values are these are directly added to the AndroidManifest.xml in the .aar file.
+        manifestPlaceholders = [onesignal_app_id: '${onesignal_app_id}',
                                 // Project number pulled from dashboard, local value is ignored
-                                onesignal_google_project_number: 'REMOTE']
+                                onesignal_google_project_number: '${onesignal_google_project_number}']
         minSdkVersion 15
         consumerProguardFiles 'consumer-proguard-rules.pro'
     }