From #9a894a we began using the content-type from the ResponseEntity
but cross-checking it still against the requested content type.
Arguably there isn't any purpose in cross-checking. The only possible
outcomes are: a) it's compatible or b) it's not, which would result in
406 (NOT_ACCEPTABLE). As we've been given explicitly the media type to
use, it makes little sense to send 406, ignoring the wish to use that
content type.
Issue: SPR-16251