GeoServer uses invalid mime type for GML 3.2 responses

GeoServer WFS 2.0 responses encoded in GML 3.2 use "text/xml; subtype=gml/3.2" as mime-type b default. This is an invalid mime-type: http://jersey.576304.n2.nabble.com/Media-type-parse-error-td6445421.html

The mime-type recommended by OGC WFS 2.0 specification is "application/gml+xml; version=3.2", although some examples in the specification use "text/xml; subtype=gml/3.2" (maybe not updated examples).

GeoServer seems to be aware of the two mime-types (but always use the wrong one):
https://github.com/geoserver/geoserver/blob/master/src/wfs/src/main/java/org/geoserver/wfs/xml/GML32OutputFormat.java#L42-L44