Lighten header nav badge colors

What does this MR do?

Lightens the badge counter colors in the header navigation by using the 400 variables until #212690 (comment 315782715) can be implemented.

Before	After

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

N/A

Security

N/A