message: 1. use optional: true when fetching backstageidentity which doesn't prompt sign-up if no session is found
  2. use Progress bar when the logic is happening
  3. remove redundant showLoginPage
diff: @@ -98,7 +98,18 @@ export const SingleSignInPage = ({
  useEffect(() => {
  const login = async () => {
  try {
  - const identity = await authApi.getBackstageIdentity();
  + let identity;
  + // Do an initial check if any logged-in session exists
  + identity = await authApi.getBackstageIdentity({
  + optional: true,
  + });
  +
  + // If no session exists, show the sign-in page
  + if (!identity) {
  + identity = await authApi.getBackstageIdentity({
  + instantPopup: true,
  + });
  + }
  const profile = await authApi.getProfile();
  onResult({
  @@ -111,9 +122,6 @@ export const SingleSignInPage = ({
  await authApi.signOut();
  },
  });
  -
  - // Don't show if login is successful
  - setShowLoginPage(false);
  } catch (err) {
  // User closed the sign-in modal
  setError(err);
  @@ -162,7 +170,9 @@ export const SingleSignInPage = ({
  </Grid>
  </Content>
  </Page>
  - ) : null;
  + ) : (
  + <Progress />
  + );
  };
  export const SignInPage = (props: Props) => {
  