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