Full-screen flash as server-side rendered HTML is re-rendered in the browser

[ybnd]

Describe the bug

When running in production mode, SSR content disappears completely for a moment before it is replaced with CSR content.

Happens on many different pages, but is especially noticeable on the search page.
Could be due to lazy themed components, since it's less severe on the home page which is mostly eager.

To Reproduce

Go to https://demo.dspace.org/search
You'll see the page load in nicely at first, then disappear for, then load in again.
You may have to turn on CPU throttling in your browser to make more obvious.

Expected behavior

SSR content should be re-rendered with minimal flashing for better UX.

Related work

More details + example video: #3709 (review)
Regression into #1357