Fix flutter validate() problem with drawable layouts

This is a bit of an odd one related to not updating the flutter runtime since we moved to rive_native.

@drawsgood and I observed that sometimes nested artboards weren't rendering properly to the stage (the nested artboard would appear as an empty node). I narrowed this down to whenever a file contained a layout with either a fill or stroke.

The reason this was happening is because when we add a nested artboard, we use genRuntimeFile, which exports, then imports and validates the objects in the file. During the validation, if the file had a layout with a fill, the fill would attempt to validate, one of the conditions of which is that it's parent is a ShapePaintContainer. LayoutComponent IS a ShapePaintContainer, BUT the validate() happens against the flutter object, and since we haven't pushed updates to flutter, LayoutComponent there is NOT a ShapePaintContainer.

The easiest fix for this is to just add the bits to LayoutComponent in flutter related to extending ShapePaintContainer. I think this should be ok since the added code doesn't have anything to do with rive_native and the new rendering pathway.

One question I have is whether we should be continuing to validate against the flutter objects when it comes to nested artboards, now that we're using rive_native. @luigi-rosso perhaps we can discuss further when you are back in office.

Diffs=
c3137b923 Fix flutter validate() problem with drawable layouts (#7727)
d9f5701ec add listener actions support for databind (#7710)
dcb165130 Fix alignment when flex wrap enabled (#7722)
fbfa3b545 Buildsystem fixes for build_rive.sh and PLS shaders (#7716)
405ca998b add click event support (#7668)
4732c37b5 Improve layout animation (#7712)
a56419984 Simple procedural text rendering API (#7701)
d6d79132b Add a test for nested events triggering listener in parent (#7709)
657f65e1c Fix for nested events in CPP (#7708)
0a11e599f Add a build_rive.sh script to unify the premake5 build process (#7691)
d25b9097d viewmodel transitions runtime (#7680)

Co-authored-by: Philip Chung <philterdesign@gmail.com>

.rive_head

@@ -1 +1 @@
-462725b0766c65fe6b69530e86cd0de46a8795b3
+c3137b923ca5d62771f85dcae10afcba6de083d3

lib/src/rive_core/layout_component.dart

@@ -10,6 +10,8 @@ import 'package:rive/src/rive_core/component_dirt.dart';
 import 'package:rive/src/rive_core/container_component.dart';
 import 'package:rive/src/rive_core/layout/layout_component_style.dart';
 import 'package:rive/src/rive_core/node.dart';
+import 'package:rive/src/rive_core/shapes/paint/shape_paint_mutator.dart';
+import 'package:rive/src/rive_core/shapes/shape_paint_container.dart';
 import 'package:rive/src/rive_core/world_transform_component.dart';
 import 'package:rive_common/layout_engine.dart';
 import 'package:rive_common/math.dart';
@@ -36,7 +38,7 @@ class LayoutAnimationData {
   LayoutAnimationData(this.fromBounds, this.toBounds);
 }
 
-class LayoutComponent extends LayoutComponentBase {
+class LayoutComponent extends LayoutComponentBase with ShapePaintContainer {
   bool _forceUpdateLayoutBounds = false;
 
   LayoutComponentStyle? _style;
@@ -139,6 +141,33 @@ class LayoutComponent extends LayoutComponentBase {
         interpolationTime > 0;
   }
 
+  @override
+  void onPaintMutatorChanged(ShapePaintMutator mutator) {
+    // The transform affects stroke property may have changed as we have a new
+    // mutator.
+    paintChanged();
+  }
+
+  @override
+  void onStrokesChanged() => paintChanged();
+
+  @override
+  void onFillsChanged() => paintChanged();
+
+  void paintChanged() {
+    addDirt(ComponentDirt.path);
+
+    // Add world transform dirt to the direct dependents (don't recurse) as
+    // things like ClippingShape directly depend on their referenced Shape. This
+    // allows them to recompute any stored values which can change when the
+    // transformAffectsStroke property changes (whether the path is in world
+    // space or not). Consider using a different dirt type if this pattern is
+    // repeated.
+    for (final d in dependents) {
+      d.addDirt(ComponentDirt.worldTransform);
+    }
+  }
+
   void markLayoutNodeDirty() {
     _layoutNode.markDirty();
     artboard?.markLayoutDirty(this);