Do not include proxy apps in graphs

src/system.js

@@ -10,6 +10,7 @@ exports = module.exports = {
 const apps = require('./apps.js'),
     assert = require('assert'),
     BoxError = require('./boxerror.js'),
+    constants = require('./constants.js'),
     debug = require('debug')('box:disks'),
     df = require('@sindresorhus/df'),
     docker = require('./docker.js'),
@@ -41,6 +42,8 @@ async function getAppDisks(appsDataDisk) {
 
     const allApps = await apps.list();
     for (const app of allApps) {
+        if (app.manifest.id === constants.PROXY_APP_APPSTORE_ID) continue;
+
         if (!app.storageVolumeId) {
             appDisks[app.id] = appsDataDisk;
         } else {