Compressed UI nodes that are not a multiple of 4 cause hard to read errors on WebGPU

## How can Bevy's documentation be improved?

Use this ktx2 image: [splash.zip](https://github.com/user-attachments/files/22548403/splash.zip)
and this code:
```rust
use bevy::prelude::*;

fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(
Startup,
|asset_server: Res, mut commands: Commands| {
commands.spawn(ImageNode::new(asset_server.load("images/splash.ktx2")));
commands.spawn(Camera2d);
},
)
.run();
}
```
in 0.16, this rendered fine, but in 0.17 it crashes. On native, you get a fine error message

it could be nicer if it included the texture name, but it's alright. However, run this with `bevy run --feature bevy/webgpu web` and your browser will show this:

eek! what does any of this mean? Why is my screen black???