Spring Deprecate ignoreDefaultModelOnRedirect property and set to true by default

It's been a long time since this API and available options have been considered, and as per the discussion under #28069, we should review for potential changes towards 6.0.

One option would be to provide a Rendering API that aligns with what is available in WebFlux.

In the very least, we can deprecate the ignoreDefaultModelOnRedirect option on RequestMappingHandlerAdapter and change its default setting.

Comment From: rstoyanchev

The property is now deprecated and set to true by default. This also matches default settings in Boot.