don't use gzip handler for sse (#15517)

Co-authored-by: Kasey Kirkham <kasey@users.noreply.github.com>
(cherry picked from commit c21fae239f)

beacon-chain/rpc/endpoints.go

@@ -1138,7 +1138,6 @@ func (s *Service) eventsEndpoints() []endpoint {
 			name:     namespace + ".StreamEvents",
 			middleware: []middleware.Middleware{
 				middleware.AcceptHeaderHandler([]string{api.EventStreamMediaType}),
-				middleware.AcceptEncodingHeaderHandler(),
 			},
 			handler: server.StreamEvents,
 			methods: []string{http.MethodGet},

changelog/kasey_gzip-skip-sse.md

@@ -0,0 +1,2 @@
+### Fixed
+- Do not apply the gzip middleware to the event stream API.