feat: Convert helpers to use JS files

packages/backend/src/helpers/billing/index.ee.js

@@ -0,0 +1,18 @@
+import appConfig from '../../config/app';
+import paddleClient from './paddle.ee';
+import paddlePlans from './plans.ee';
+import webhooks from './webhooks.ee';
+
+const paddleInfo = {
+  sandbox: appConfig.isProd ? false : true,
+  vendorId: appConfig.paddleVendorId,
+};
+
+const billing = {
+  paddleClient,
+  paddlePlans,
+  paddleInfo,
+  webhooks,
+};
+
+export default billing;