A delivery set Content-Type from the event's ContentType and then
added the inbound Content-Type from the event's stored headers, so
the target could receive two values. The inbound Content-Type is no
longer forwarded from the stored headers; the receiver already saved
it as the event's ContentType.
Which value wins is now stated at applyRequestHeaders: a Content-Type
configured on the target, otherwise the event's ContentType,
otherwise none.
Model: opus-5-5