message: fix: do not throw error when server response with empty array errors
  We use an empty array in case of no error for consistent response type.
diff: @@ -71,7 +71,7 @@ export class SchemaFetcher {
  return new Promise((resolve, reject) => {
  execute(link, operation).subscribe({
  next: schemaData => {
  - if (schemaData && (schemaData.errors || !schemaData.data)) {
  + if (schemaData && ((schemaData.errors && schemaData.errors.length > 0) || !schemaData.data)) {
  throw new Error(JSON.stringify(schemaData, null, 2))
  }
  