Docs: dark mode doesn't work in search box

[DomeT99]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the issue has not already been raised

Issue

Hi guys!
While browsing the documentation I realized a small graphic bug: if you have the dark mode active, the first time you land on the page, the search box remains in light mode.

This is the screen:

[Eomm]

Fixed with docusaurus v3