[EUI+] Investigate pages freezing on dev during HMR

[weronikaolejniczak]

The purpose of this task is to investigate pages freezing locally during hot module replacement.

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Steps to reproduce:

1. Open the terminal and run yarn to install dependencies.
2. Build all local dependency packages: yarn workspaces foreach -Rpti --from @elastic/eui-website run build.
3. Start the local development server: yarn start.
4. Go to any page in the new docs.
5. Make changes in the code of the docs (tip: if you scroll to the bottom and click on "Edit this page", it's going to redirect you to the source of the page).

Current behavior:

The page freezes for a significant time (sometimes for several seconds).

Expected behavior:

The page doesn't freeze or freezes for much less time that doesn't impair local development.