Input sticking when moving game window at the same time

## Bevy version

`0.6`

## Operating system & version

Windows 11

## What you did

I applied input while moving the game window around at the same time, then released the input key.

## What you expected to happen

Input should stop being applied after releasing input.

## What actually happened

The input was still being applied even after releasing the key while moving the game window.

## Additional information
This is the player movement system I was using when I came across this bug.
```
fn move_player(
keyboard_input: Res>,
time: Res,
mut q_player: Query<(&Player, &mut Transform)>,
) {
let (_, mut transform) = q_player.single_mut();
let key = keyboard_input.get_pressed().next();
let speed = 200.0;
if let Some(ref key) = key {
match key {
KeyCode::A => transform.translation.x -= speed * time.delta_seconds(),
KeyCode::D => transform.translation.x += speed * time.delta_seconds(),
KeyCode::W => transform.translation.y += speed * time.delta_seconds(),
KeyCode::S => transform.translation.y -= speed * time.delta_seconds(),
_ => (),
}
}
}
```