Convert drag/drop sort to operate on groups instead

[dsamojlenko]

Summary | Résumé

Drag/Drop sorting for TreeView.
Old function was operating on TreeData and was overly complicated and not working correctly.
Converted to operating on Groups data which has proven easier/cleaner.

Drag/Drop test cases:

• Drag/drop root level groups at root level
• Cannot drag/drop root level groups to group level
• Drag/drop items within a group
• Select multiple items and drag/drop within a group
• Drag/drop items across groups
• Select multiple items in a group and drag/drop to another group
• Select items in multiple groups and drag/drop to another group
• Select items in multiple groups and drag/drop to different position in one of the selected groups
• Cannot select an item and a group and drag/drop anywhere

[github-actions]

🧪 Review environment

https://wmrtjnwxmfcghgerfwuflfplbi0jsahc.lambda-url.ca-central-1.on.aws/