Instance tables refactor part 4: replace ArtboardGroups with multi-row Instances<Artboard> (#2265)

* Clean up dyn_any usages

* Migrate ArtboardGroup to ArtboardGroupTable (not yet flattened)

* Reorder graphical data imports

* Flatten and remove ArtboardGroup in favor of ArtboardGroupTable

* Fix test

node-graph/graph-craft/src/imaginate_input.rs

@@ -1,11 +1,10 @@
 use dyn_any::DynAny;
 use graphene_core::Color;
+
 use std::borrow::Cow;
 use std::fmt::Debug;
-use std::sync::{
-	atomic::{AtomicBool, Ordering},
-	Arc, Mutex,
-};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, Mutex};
 
 #[derive(Default, Debug, Clone, DynAny, specta::Type)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]