Allow header background colour specific for editing only

[pbaddock]

Prerequisites

• I have searched for similar features requests in both open and closed tickets and cannot find a duplicate.
• The feature is still missing in the latest stable version of Elementor ( Elementor Pro )

What problem is your feature request going to solve? Please describe.

When setting a header with a transparent background (which I often want to do to place the menu over a background image) - often I want my menu font to be white, but the default white background means its effectively hidden and makes things difficult when editing.

Describe the solution you'd like

It would be great if it was possible to set a background colour just when editing but which was not applied when viewed from the front end.

Describe alternatives you've considered

Thought about whether there could be a dark mode or some other more general editor mode solutions but seems like that might be overkill and just specifically setting a background color would do the job.

Additional context

No response