(BREAKING) Make AacFlController.AnimatorController read-only:

- Breaking changes:
  - Make AacFlController.AnimatorController read-only.

Packages/dev.hai-vr.animator-as-code.v1/V1/Editor/Aac.cs

@@ -83,6 +83,7 @@ namespace AnimatorAsCode.V1
             return ContainerMode == Container.Everything ? AssetContainer : null;
         }
 
+        /// Values that define how created assets should be added to the AssetContainer.
         public enum Container
         {
             /// Store all created assets in the AssetContainer.
@@ -682,7 +683,7 @@ namespace AnimatorAsCode.V1
     public class AacFlController
     {
         /// Exposes the underlying Unity AnimatorController.
-        public AnimatorController AnimatorController; 
+        public readonly AnimatorController AnimatorController; 
         
         private readonly AacConfiguration _configuration;
         private readonly AacFlBase _base;