Allow Scripted Authentication modules to not run client-side script at all

Currently even if you disable the client-side script in a Scripted authentication module it still renders a ScriptTextOutputCallback, just with a script that will immediately self-submit the form. For REST clients and browsers with Javascript disabled, this is an annoying extra step that shouldn't be necessary if client-side scripting is not actually required.

Suggest that the Scripted auth module instead just immediately runs the server-side script with a null clientScriptOutputData variable if client-side script is disabled.