`Collider::convex_mesh()` produces surprising results

When using `Collider::convex_mesh()`, I seem to consistently get a center of mass "outside" the shape, causing the resulting body to behave incorrectly. The following is a simple repro case with a regular tetrahedron, which I expect to fall, collide with the "table", and come to rest quickly. Instead, it will fall and then begin spinning for an extended duration.

I suspect that I'm specifying the indices incorrectly, but there is no documented ordering or other restrictions, either on `Collider::convex_mesh()` or the underlying implementations.

```rs
use bevy::prelude::*;
use bevy_rapier3d::prelude::*;

fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_plugins(RapierPhysicsPlugin::::default())
.add_plugins(RapierDebugRenderPlugin::default())
.add_systems(Startup, set_up_camera)
.add_systems(Startup, set_up_physics)
.add_systems(Update, bevy::window::close_on_esc)
.run();
}

fn set_up_camera(mut commands: Commands) {
commands.spawn(Camera3dBundle {
projection: Projection::Perspective(Default::default()),
transform: Transform::from_xyz(0.0, 10.0, 0.0).looking_at(Vec3::ZERO, Vec3::Z),
..default()
});
}

fn set_up_physics(mut commands: Commands) {
commands
.spawn(Collider::cuboid(100.0, 0.1, 100.0))
.insert(TransformBundle::from(Transform::from_xyz(0.0, 0.0, 0.0)));

commands
.spawn(RigidBody::Dynamic)
.insert(Velocity::default())
.insert(
Collider::convex_mesh(
vec![
Vec3::new(-0.5, 0.0, 0.0),
Vec3::new(0.5, 0.0, 0.0),
Vec3::new(0.0, 0.0, 0.866025404),
Vec3::new(0.0, 0.816496581, 0.433012702),
],
&[[0, 1, 2], [0, 1, 3], [0, 2, 3], [1, 2, 3]],
)
.unwrap(),
)
.insert(TransformBundle::from(Transform::from_xyz(0.0, 9.0, 0.0)));
}
```