onSuccess = function() {
    component.dispose();
    firebaseui.auth.widget.handler.handle(
        firebaseui.auth.widget.HandlerName.EMAIL_LINK_SIGN_IN_SENT,
        app,
        container,
        email,
        onCancelClick,
        opt_pendingCredential);
  }
Handles sending email link for either sign in or link. If pending
credential is passed, send email for link. Otherwise, send email for sign in.

@param {!firebaseui.auth.AuthUI} app The current FirebaseUI instance whose
    configuration is used.
@param {!firebaseui.auth.ui.page.Base} component The current UI component.
@param {string} email The user's email.
@param {function()} onCancelClick Callback to invoke when the back button is
    clicked in email link sign in sent page.
@param {function(*)} onError Callback to invoke when error occurs while
    sending the sign in email link.
@param {?firebaseui.auth.PendingEmailCredential=} opt_pendingCredential The
    pending credential to link to a successfully signed in user.