message: Fix failing testbed tests - React to change in return type of
  iModelDb.elements.getElementJson.
diff: @@ -57,7 +57,7 @@ export class IModelReadGatewayImpl extends Gateway implements IModelReadGateway
  const elementProps: string[] = [];
  for (const id of elementIds) {
  try {
  - elementProps.push(iModelDb.elements.getElementJson(JSON.stringify({ id })));
  + elementProps.push(JSON.stringify(iModelDb.elements.getElementJson(JSON.stringify({ id }))));
  } catch (error) {
  if (elementIds.size === 1)
  throw error; // if they're asking for more than one element, don't throw on error.
  