message: fix token event not being canceled on promise rejection
diff: @@ -89,7 +89,7 @@ export class OdspDocumentService implements IDocumentService {
  logger,
  { docId: hashedDocumentId });
  - this.getStorageToken = (refresh: boolean, name?: string) => {
  + this.getStorageToken = async (refresh: boolean, name?: string) => {
  if (refresh) {
  // Potential perf issue:
  // Host should optimize and provide non-expired tokens on all critical paths.
  @@ -97,9 +97,9 @@ export class OdspDocumentService implements IDocumentService {
  this.logger.sendTelemetryEvent({ eventName: "StorageTokenRefresh" });
  }
  const event = PerformanceEvent.start(this.logger, { eventName: `${name || "OdspDocumentService"}_GetToken` });
  - let token: Promise<string | null>;
  + let token: string | null;
  try {
  - token = getStorageToken(this.siteUrl, refresh);
  + token = await getStorageToken(this.siteUrl, refresh);
  } catch (error) {
  event.cancel({}, error);
  throw error;
  