Edit mode: inspector doesn't update new assets

[madjin]

The code editor updates with new assets (dragged n dropped primitives from inventory into scene) but not the scene editor in inventory tab

[jbaicoianu]

Fixed, this was because the scene tree only shows objects with persist="true" set, and the editor wasn't setting that parameter for newly-spawned objects. The newly-updated editor does that, and I also set persist="true" for files that are drag-dropped from the local system