C4 WebBrowserContainer doesn't allow changing fillColor

[JulioC]

Preflight Checklist

• [x] I agree to follow the Code of Conduct that this project adheres to.
• [x] I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Describe the bug

When changing the colros of C4 WebBrowserContainer it doesn't apply the fillColor to the background and strokeColor for the borders as one would expect. It instead uses the fillColor to set the frame color and leaves the background always unchanged.

To Reproduce

1. Use default C4 shape library
2. Create a WebBrowserContainer shape
3. Set fill and stroke colors to anything (red and green maybe)
4. See the background color unchanged

Expected behavior

Fill should change the background color A clear and concise description of what you expected to happen.

Screenshots

The image below shows how this shape behaves in comparission to others from the same collection:

draw.io version (In the Help->About menu of the draw.io editor):

• draw.io version: 20.2.3

Additional context

The offending code appears to be in https://github.com/jgraph/drawio/blob/dev/src/main/webapp/shapes/mxC4.js#L185

The shape doesn't use stroke color for anything. This change might break visuals for existing diagrams with customized colors for this components (probably not many diagrams).