Viewport debug example in web has a visual difference between the two uinode trees

## Bevy version

0.14 from the browser: https://bevyengine.org/examples/ui-user-interface/viewport-debug/

## \[Optional\] Relevant system information

`Version 126.0.6478.183 (Official Build) (arm64)`

## What you did

Go here https://bevyengine.org/examples/ui-user-interface/viewport-debug/

## What went wrong

Look at the visual diff / shift on webgl2 and webgpu examples. The example comment says:

> If there are no problems both layouts should be identical, except for the color of the margin changing which is used to signal that the displayed uinode tree has changed

So I'm expecting this shift to not happen, so looks like a bug to me.

https://github.com/user-attachments/assets/fbe4c604-c55a-4372-8239-90edda29cbe5

https://github.com/user-attachments/assets/d62d990e-1974-4517-b2cb-fa8035fc11c2

But it works fine on macos:

https://github.com/user-attachments/assets/20144740-40cb-48c9-bc78-882a0d1a6fff