fix(list): fix mobile device dragging with nested lists

[driskull]

Related Issue: #9521

Summary

• Makes sure that connectSortableComponent isn't called during an active drag of a sortable item.
  • Previously, mutation observers were calling connectSortableComponent during a drag
  • This caused the existing implementation to be destroyed and a new one created which left the user in a frozen state.
  • This only occurred on mobile devices because mobile devices do not use native drag and drop with Sortable.js
• The fix makes sure that connectSortableComponent and disconnectSortableComponent do nothing during an active drag.

[jcfranco]

Changes LGTM!

Would current tests cover these changes or is there mobile-specific behavior in SortableJS that can't be tested? Possibly related, are we waiting for #8297 to improve/add coverage for this?

[driskull]

Would current tests cover these changes or is there mobile-specific behavior in SortableJS that can't be tested? Possibly related, are we waiting for #8297 to improve/add coverage for this?

Yeah we can't currently test it because we need mobile testing of sortablejs. We would need to do some sort of browser identification spoofing alongside the automated test.