The attribute was previously removed only before exception resolution
in the DispatcherServlet in order to allow error rendering to make an
independent choice on content negotation.
However, Boot rendering happens later in an ERROR dispatch which could
also be a nested dispatch on some servers. So the attribute must also
generally be removed prior to mapping.
We also move the methods where this is done to the base
RequestMappingInfoHandlerMapping class which also deals with the
produces condition and where the producible attribute is added in the
first place.
Closes gh-24466
68b980f849