feat: S2 DnD docs and followups (#10082)
* revert listlayout change now that insertion indicators reserve 0 height
* shorten treeview docs copy
* share listview drag button styling with treeview
* use svg and share same implementation
* dnd pages in s2, links might be broken
* fix inconsistencies and center gridlist dropzone text
* fix treeview highlight selection on item drop fill color and root drop border radius
* add dnd to test apps and fix docs types
* fix image drop example
* ugh copy pasta
* fix drag handle alignment
* unify drag handle styles
done via isFocusVisibleWithinRow render prop support in TableCells and isFocusVisibleWithin render prop support in GridList row
* fix imports
