Cleanup of unnecessary items in user scripts config. JSON

Fixes #5456

scripts/lua/modules/callback_definitions/flow/zero_tcp_window.lua

@@ -3,7 +3,6 @@
 --
 
 local alerts_api = require("alerts_api")
-local alert_severities = require "alert_severities"
 local user_scripts = require("user_scripts")
 local alert_consts = require("alert_consts")
 local flow_alert_keys = require "flow_alert_keys"
@@ -21,7 +20,6 @@ local script = {
   alert_id = flow_alert_keys.flow_alert_zero_tcp_window,
 
   default_value = {
-   severity = alert_severities.warning,
   },
   
   gui = {