[Toolbar] set background to transparent

[Diaan]

Provide a general summary of the issue here

when a toolbar is on a coloured background you get some weird stuff because the background is set to --sl-elevation-surface-raised-default

🤔 Expected Behavior?

toolbar has a transparent background

😯 Current Behavior

white background

💁 Possible Solution

No response

🖥️ Steps to Reproduce

https://storybook.sanomalearning.design/?path=/story/layout-panel--basic&args=elevation:sunken

What browsers are you seeing the problem on? (only for bugs in code)

Chrome

If other, please specify.

No response

What operating system are you using?

MacOS

👤 Your name

Diana

🧢 Your product/team

SLDS

🎨 Your Theme(s)

Sanoma Learning