Dark mode Preferences Header is in light mode

Summary

When on the preferences page in dark mode, the site header is rendered in light mode. This problem does not happen in any of the other modes, even in "Dark", which is not "Dark mode"

Steps to reproduce

1. Click on the user Avatar Dropdown
2. Click on Settings
3. Click on Preferences
4. Select dark mode in navigation theme
5. The rest of the page should switch to dark mode (you may have to reload)
6. The top bar should be rendered in light mode instead of dark mode

What is the current bug behavior?

The top bar is not rendered in dark mode

What is the expected correct behavior?

The top bar should be rendered in dark mode

Relevant logs and/or screenshots