fix: check for EOF body in upstream influxdb listener

Throughout the influx parsing logic there are checks for receiving an
EOF body. When received the parsing logic returns. When content is gzip
we check for any error and return that error, but do not do any specific
chesk for EOF.

Fixes: #10900

plugins/inputs/influxdb_listener/influxdb_listener.go

@@ -346,7 +346,9 @@ func (h *InfluxDBListener) handleWriteUpstreamParser(res http.ResponseWriter, re
 	if req.Header.Get("Content-Encoding") == "gzip" {
 		var err error
 		body, err = gzip.NewReader(body)
-		if err != nil {
+		if err == influx_upstream.ErrEOF {
+			return
+		} else if err != nil {
 			h.Log.Debugf("Error decompressing request body: %v", err.Error())
 			if err := badRequest(res, err.Error()); err != nil {
 				h.Log.Debugf("error in bad-request: %v", err)