message: isUserInternal based on billable flag
diff: @@ -753,6 +753,10 @@ export default class StripeBillingIntegration extends BillingIntegration {
  }
  private isUserInternal(user: User): boolean {
  + // Check user's flag 'billable'
  + if (Utils.isBoolean(user.billable)) {
  + return !user.billable;
  + }
  // slf
  if (this.tenant.id === '5be7fb271014d90008992f06') {
  const email = user?.email?.toLocaleLowerCase();
  