feat: Implement getInvoices graphQL query

packages/backend/src/graphql/queries/get-invoices.ee.ts

@@ -0,0 +1,17 @@
+import Context from '../../types/express/context';
+import Billing from '../../helpers/billing/index.ee';
+
+const getInvoices = async (
+  _parent: unknown,
+  _params: unknown,
+  context: Context
+) => {
+  const subscription = await context.currentUser.$relatedQuery('subscription');
+  const invoices = await Billing.paddleClient.getInvoices(
+    Number(subscription.paddleSubscriptionId)
+  );
+
+  return invoices;
+};
+
+export default getInvoices;