Item copy can result in broken courseassets in other items

[dancgray]

Expected Behaviour

Copying an item with pre-populated assets and replacing the assets in the copied item should not affect the original item's assets.

Actual Behaviour

On removal of the asset in the copied item the original items asset is removed.

Steps to Reproduce

1. add an accordion and create an item selecting a graphic
2. copy that item and remove the asset in the copied item
3. original item's asset courseasset record is removed

Versions

• Authoring Tool Version: v0.8.1
• Framework Version: v2.4
• Node.js Version: v10.15.3
• MongoDB Version: v3.6
• Operating System: n/a
• Browser: n/a

[dancgray]

Also see #2348 . There are inconsistencies in the way course assets are created or deleted. There is no courseasset creation on copy/paste item and no courseasset deletion on item deletion.

@tomgreenfield @taylortom @canstudios-nicolaw do you think we should just "patch" this in scaffoldListView.js or fix in a more fundamental way?