fix: ensure @rollup/plugin-commonjs v22 update builds correctly

[fwouts]

Description

This PR, which isn't meant to be merged into main directly, fixes the build failures seen in #7886.

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[fwouts]

Not sure why these failing tests didn't pop up in my local run, I'll fix this up.

[fwouts]

Test failures appear due to the Rollup upgrade. As far as I understand, the vite:modulepreload-polyfill plugin is now, in some cases (HMR in particular?) unable to catch the load event. I'll explore further, but I'll close this PR for now as it's clearly not ready.

Edit: in fact, it was probably because I replaced loadResult == null with !loadResult :)