Docs - Update Drag and Drop guidelines

[bekah-stephens]

Description

In PFv5 there was a blue bounding box that appeared on drag, but that’s no longer the case.

Recommendation / Fix

1. Update page content to explain that on drag there is a “ghost” version of the item being dragged.

[kaylachumley]

we also no longer support the error state red bounding box on drag so lets remove that part of the guidelines until design brainstorms a new approach