Gitter Beta is broken (babel runtime dependency)
Going to the https://beta.gitter.im/gitterHQ/gitter results in an error after a long request which times out.
## Server logs
```
ssh gitter-beta-01.beta.gitter
sudo vim /var/log/upstart/gitter-web-2.log
```
```
(node:23458) UnhandledPromiseRejectionWarning: Error: Cannot find module '@babel/runtime/helpers/defineProperty' from '/opt/gitter/gitter-webapp/output/assets/js'
at Function.module.exports [as sync] (/opt/gitter/gitter-webapp/node_modules/resolve/lib/sync.js:74:15)
at r (/opt/gitter/gitter-webapp/node_modules/vue-server-renderer/build.dev.js:9297:44)
at Object.<anonymous> (webpack:/external "@babel/runtime/helpers/defineProperty":1:0)
at n (webpack/bootstrap:33:0)
at Module.<anonymous> (public/js/vue/thread-message-feed/index.js:12:50)
at n (webpack/bootstrap:33:0)
at server-bundle.js:1:985
at Object.<anonymous> (webpack:/external "@babel/runtime/helpers/defineProperty":1:0)
at evaluateModule (/opt/gitter/gitter-webapp/node_modules/vue-server-renderer/build.dev.js:9303:21)
at /opt/gitter/gitter-webapp/node_modules/vue-server-renderer/build.dev.js:9361:18
at new Promise (<anonymous>)
at /opt/gitter/gitter-webapp/node_modules/vue-server-renderer/build.dev.js:9353:14
at Object.renderToString (/opt/gitter/gitter-webapp/node_modules/vue-server-renderer/build.dev.js:9529:9)
at renderToString (/opt/gitter/gitter-webapp/server/handlers/renderers/vue-ssr-renderer.js:107:19)
(node:23458) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 18)
2019-11-12T14:57:25.502Z - warn: HTTP request still pending after 60000ms routeIdentifier=app-main-frame, userId=5cc868bdae37931480dc3959, method=GET, path=/gitterHQ/gitter
```
issue