Collider user change detection fails when its position is updated by the engine

[newDINO]

When user changes a collider (such as setting voxels), the modification may not be added to ModifiedColliders, because the collider is already marked as Modified. This is fine when the collider is already added to ModifiedColliders, but during the last sub step of the engine update, ModifiedColliders is cleared, which causes user changes not being captured by the engine, causing strange behaviors such as inaccurate center of mass.

[newDINO]

I created a simplest fix I can think of at #898. However, It may not be the best due to my lack of understanding of the full engine.

[newDINO]

#900 fix works in my use case😉