Use GlobalTarget when reading the position of the Gizmo camera

[AlexAegis]

Description

Found a problem where, if the Gizmo camera is parented to something, then the gizmo will appear off.

(In my top-down game the camera is parented to a "selfie stick" to make it easier to move without having to worry about its angle towards the ground)

The fix looked easy hence the PR, it should just read the GlobalTransform of the camera instead of the local.

Bug Demo

In another branch I made a very rudimentary change to your example to showcase the bug, I only modified the scene.rs file: https://github.com/AlexAegis/transform-gizmo/blob/non-global-camera-bug-demo/examples/bevy/src/scene.rs

edit: I deleted my fork, here's the changed part of the example for reference:

#[derive(Component)]
struct SelfieStick;

fn move_camera(mut selfie_stick_query: Query<&mut Transform, With<SelfieStick>>) {
    for mut stick_transform in selfie_stick_query.iter_mut() {
        stick_transform.translation.x -= 0.01;
        stick_transform.translation.y += 0.01;
    }
}

fn setup_scene(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    let camera_transform = Transform::from_xyz(5.0, 5.0, 5.0);

    commands
        .spawn((TransformBundle::IDENTITY, SelfieStick))
        .with_children(|parent| {
            parent.spawn((
                Camera3dBundle {
                    transform: camera_transform.looking_at(Vec3::ZERO, Vec3::Y),
                    ..default()
                },
                GizmoCamera,
            ));
        });

[urholaukkarinen]

Thanks!