Updates [Discord] badge for API changes (#4475)

* Updates Discord badge for API changes

* Update discord.service.js

* Update discord.service.js

* cr fix

services/discord/discord.service.js

@@ -1,12 +1,11 @@
 'use strict'
 
 const Joi = require('@hapi/joi')
+const { nonNegativeInteger } = require('../validators')
 const { BaseJsonService } = require('..')
 
 const discordSchema = Joi.object({
-  members: Joi.array()
-    .allow(null)
-    .required(),
+  presence_count: nonNegativeInteger,
 }).required()
 
 const documentation = `
@@ -77,7 +76,6 @@ module.exports = class Discord extends BaseJsonService {
 
   async handle({ serverId }) {
     const data = await this.fetch({ serverId })
-    const members = Array.isArray(data.members) ? data.members : []
-    return this.constructor.render({ members: members.length })
+    return this.constructor.render({ members: data.presence_count })
   }
 }