.drag() on an element outside the viewport does not work

If you do `.drag()` on an element outside the viewport, it does not work. This is because https://developer.mozilla.org/en-US/docs/Web/API/DocumentOrShadowRoot/elementFromPoint does not work outside the viewport.

I think we should detect this and throw an error (or warning) letting people know.

It's possible we could scroll to to make this work for locations that are not negative.

Start at the .drag() implementation and reproduce the behavior with an element outside the viewport, checking the documented elementFromPoint limitation. Decide whether the accepted outcome is an error, warning, or scrolling behavior, then verify that the chosen behavior is covered by the relevant drag tests; no repository file or test path is named in the issue.

Written by the indexing model from the issue text.