Use proper exception when media type handling is incorrect

This is not only how RESTEasy Classic behaves,
but also the exception that RESTEasy Reactive
itself uses in other places where media type
mapping fails

Fixes: #36798

independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/handlers/MediaTypeMapper.java

@@ -7,6 +7,7 @@
 import java.util.List;
 import java.util.Map;
 
+import jakarta.ws.rs.NotSupportedException;
 import jakarta.ws.rs.WebApplicationException;
 import jakarta.ws.rs.core.HttpHeaders;
 import jakarta.ws.rs.core.MediaType;
@@ -73,7 +74,7 @@ public void handle(ResteasyReactiveRequestContext requestContext) throws Excepti
             selectedHolder = resourcesByConsumes.get(MediaType.WILDCARD_TYPE);
         }
         if (selectedHolder == null) {
-            throw new WebApplicationException(Response.status(Response.Status.UNSUPPORTED_MEDIA_TYPE).build());
+            throw new NotSupportedException("The content-type header value did not match the value in @Consumes");
         }
         RuntimeResource selectedResource;
         if (selectedHolder.mtWithoutParamsToResource.size() == 1) {