Spring Security Allow auto-submit form for POST saml authentication requests to be customizable

Expected Behavior

Allow the users to render their own auto submit form similar to similar to metadata download OpenSamlMetadataResolver#entityDescriptorCustomizer

Current Behavior

The current auto submit html form for SAML requests uses arrow functions which don't work for older browser .. for example IE 11.

<script>window.onload = () => document.forms[0].submit();</script>\n"