UI does not load when JavaScript is disabled in browser

[tdonohue]

Describe the bug
If you turn off Javascript in your browser, the UI becomes unresponsive. No errors appear (at least not in the DevTools in the browser), but no page will load successfully.

UPDATE: I've determined this is caused by #1244 If I revert that PR, everything works.

To Reproduce
Steps to reproduce the behavior:

1. Turn off JS in your browser tab (e.g in Chrome, go into DevTools, select "Settings" (upper right), check "Disable Javascript")
2. Visit the demo site (any page), e.g. https://demo7.dspace.org/ in that tab. This is also reproducible when running the UI on localhost:4000 (via yarn start)

Expected behavior
For SEO purposes, the site must work (at least public pages) with Javascript disabled.

[tdonohue]

I've verified that the 7.0 Beta5 release worked properly. You could turn off Javascript and still interact with the site. So, this issue has been caused since Beta 5. So, some UI PR on our 7.0 board has broken server-side rendering (SSR). I'm attempting to narrow it down further.

[tdonohue]

After further testing/debugging, I've determined the cause to be PR #1244 (created by @atarix83 ). That PR accidentally breaks SSR. If I revert that PR locally & start the UI (via yarn start), then I can run the UI with Javascript disabled.

@atarix83 or @abollini : Is there someone from 4Science that could help fix this issue? If not, we likely will need to revert that PR prior to the 7.0 release.

(As a sidenote, it'd also be good to figure out a way to avoid this in the future... we likely need e2e tests that verify that SSR is working at even a basic level. That's not necessarily required for 7.0, but we should start investigating for 7.1 to ensure a future PR doesn't accidentally break SSR.)