unexpected change from v1: missing dragElement should result in non-sortable item

[runspired]

in v1 if a sortable-item specified a selector for the dragElement, and no such element existed, the item would be unsortable.
in v3 these items become sortable by dragging the main element.

[MelSumner]

@runspired was this a documented breaking change, or is it a bug?

[runspired]

@MelSumner it was not documented, so it's likely a bug.

That said the old behavior was a bit "odd" in that there was never support for rending with/without a drag handler available via selector and then later having that change in a new render post-initialization. In our app I migrated us to using the disabled attributes, which is a much simpler path forward for this case than having us do a difficult re-check of the DOM on each update. It might be worthwhile to simply document this as a breaking-change retroactively and mention the solution as being to use the disabled arg.