WatcherRPC's status.get is timing out

[ayrat555]

while looking into #1659 I found that
status.get is timing out when the request contains empty body with not empty content-length header. For example

curl -w "@file.txt" \
 -X POST \
 --data "{}" -H "Accept: */*" \
 -H "Accept-Encoding: gzip"  -H "Content-Length: 51876961" \
 -H "Content-Type: application/json" \
 "http://localhost:7534/status.get"

{"data":{"code":"server:internal_server_error","description":"Server has failed to render the error.","object":"error"},"service_name":"watcher_info","success":false,"version":"1.0.3+522fb32"}   

 time_namelookup:  0,004s
       time_connect:  0,005s
    time_appconnect:  0,000s
   time_pretransfer:  0,005s
      time_redirect:  0,000s
 time_starttransfer:  15,008s
                    ----------
         time_total:  15,008s

I think it's related to elixir-plug/plug#968

[unnawut]

Doesn't seem to affect overall system perf so will treat this as low priority