Updated dom layout of attahcments to prevent nested dropzones (No issue
but potential to be one) and updated edit form dropzone handling so the
dropzone item card was not as distracting.
- Fixes existing broken attachment edit tabs.
- Redesigns area to move away from old tabbed interface.
- Integrates new dropzone system, for both addition and edit.
Intended to fix positioning quirks caused by changing codemirror
instance size when you have lines that wrap and cause line height
changes. Often caused by editor toolbox expand/collapse.
This adds a debounced resize observer to refresh editor layout on size
change.
Also tweaks toolbox expand/collapse to more consistently set aria
attribute.
For #3186
