message: Fix sync failed when datasource is schema-less
diff: @@ -261,10 +261,11 @@ export class DatasourceEditor extends React.PureComponent {
  }
  syncMetadata() {
  const { datasource } = this.state;
  + // Handle carefully when the schema is empty
  const endpoint = (
  `/datasource/external_metadata/${datasource.type}/${datasource.id}/` +
  `?db_id=${datasource.database.id}` +
  - `&schema=${datasource.schema}` +
  + `&schema=${datasource.schema || ''}` +
  `&table_name=${datasource.datasource_name}`
  );
  this.setState({ metadataLoading: true });
  