Translucent window outline (window shadow) appears when moving windows with a transparent background with a transparent window

## Bevy version 0.13

The release number or commit hash of the version you're using.

## \[Optional\] Relevant system information

cargo version: cargo 1.78.0-nightly (a4c63fe53 2024-03-06)

```ignore
`SystemInfo { os: "MacOS 14.2.1 ", kernel: "23.2.0", cpu: "Apple M1", core_count: "8", memory: "16.0 GiB" }`
```

## What you did
I made the background transparent in the desk_toy example and moved the sprite around, and it ended up like this.

## What went wrong

Ghostly semi-translucent outline appeared.


Start by reproducing the issue in the desk_toy example on macOS 14.2.1 with a transparent background, then move the sprite as described. Investigate the resulting translucent window outline; done means the ghostly outline no longer appears during movement.

Written by the indexing model from the issue text.