* Add unit test to test trait collection changes occur during updates are handles correctly
* Remove handling code in ASDataController:updateWithChangeSet. Previous test should fail
* Correctly handle trait collection changes that occur mid-updates
- Currently, when there is a new trait collection, we correctly propagate it to all visible elements. However, since the propagating block is executed on main thread immediately without waiting for the background editing queue of ASDataController, not all elements are updated.
- Then to fix that, we updated ASDataController to handle these changes inside updateWithChangeSet. This works, but it doesn’t address the underlying issue.
- We now delegate the propagating task to ASDataController which schedule a block to its main serial queue after waiting for its background editing queue.
* Fix trait collection handling in ASCollectionElement
- Don't store a trait environment directly and request it when needed. The environment is often the cotaining collection/table node. Asking it for a trait collection is an upward tree traversal and can cause deadlocks. This reverts #2963.
- If the environment changes during a change set update, notify all visible elements about the change. This fixes#2959.
* Address comments
* New way to informing interaction delegate if ASCellNode get’s a setNeedsLayout call
* Remove nodeDidGetNeedsLayout as optional and better check if cell updates need to happen
* Differentiate between letting a normal display node and a cell node know that the size could have changed
* Check for _interactionDelegate is nil
* Add nullability to out pointer
* Adress comments and some renaming
