fix: add custom attributes for ecommerce events (#58)

Author: alla-uday

android/src/main/java/com/mparticle/react/MParticleModule.java

@@ -595,6 +595,9 @@ else if (isPromotion) {
         if (map.hasKey("shouldUploadEvent")) {
             builder.shouldUploadEvent(map.getBoolean("shouldUploadEvent"));
         }
+        if (map.hasKey("customAttributes")) {
+            builder.customAttributes(ConvertStringMap(map.getMap("customAttributes")));
+        }
 
         return builder.build();
     }

ios/RNMParticle/RNMParticle.m

@@ -419,6 +419,9 @@ + (MPCommerceEvent *)MPCommerceEvent:(id)json {
     if (json[@"shouldUploadEvent"] != nil) {
         commerceEvent.shouldUploadEvent = [json[@"shouldUploadEvent"] boolValue];
     }
+    if (json[@"customAttributes"] != nil) {
+        commerceEvent.customAttributes = json[@"customAttributes"];
+    }
 
     NSMutableArray *products = [NSMutableArray array];
     NSArray *jsonProducts = json[@"products"];