Content list in the sidebar is not localized

[agektmr]

Describe the bug
When a localized content is displayed, some of the contents list items on the left side is not localized.

To Reproduce
Steps to reproduce the behavior:
Go to https://developer.chrome.com/ja/docs/privacy-sandbox/feedback/

Expected behavior
"What is the Privacy Sandbox?" is translated and displayed as "プライバシー サンドボックスとは何か？".

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
I presume these translation are done through the combination of:

1. site/_data/docs/privacy-sandbox/toc.yml
2. site/_data/i18n/docs/privacy-sandbox.yml

So they are translated properly on https://developer.chrome.com/ja/docs/privacy-sandbox/ but the same logic does not seem to be applied to the content list of the left nav.

[matthiasrohmer]

Won't fix, due to the pending move to the new CMS.