Add assets precompile check to the miscellaneous tasks node (#15280)

* Add assets precompile check to the miscellaneous tasks node

* Add unrecognized js syntax

This should trip the precompile step?

* use production mode to precompile

The containerfile does this, and we don't see the same failures unless
we do too

* remove unrecognized syntax from pipeline js

This failed correctly during the build during
https://app.travis-ci.com/github/forem/forem/jobs/546569306 and
validates the test will fail if we get in this situation.

.travis.yml

@@ -90,6 +90,7 @@ jobs:
         - bundle exec bundle-audit check --update
         - bin/test-console-check
         - yarn build-storybook
+        - NODE_ENV=production RAILS_ENV=production bundle exec rake assets:precompile
     - stage: Test
       name: "E2E Seeded Node 0"
       env: