fix(ios): view model instance empty constructor

Author: HayesGordon

ios/HybridRiveView.swift

@@ -21,8 +21,8 @@ class HybridRiveView : HybridRiveViewSpec {
 
   // MARK: View Methods
   func bindViewModelInstance(viewModelInstance: (any HybridViewModelInstanceSpec)) throws {
-    guard let hybridViewModelInstance = viewModelInstance as? HybridViewModelInstance else { return }
-    riveView?.bindViewModelInstance(viewModelInstance: hybridViewModelInstance.viewModelInstance)
+    guard let viewModelInstance = (viewModelInstance as? HybridViewModelInstance)?.viewModelInstance else { return }
+    riveView?.bindViewModelInstance(viewModelInstance: viewModelInstance)
   }
   func play() throws { riveView?.play() }
   func pause() throws { riveView?.pause() }

ios/HybridViewModelInstance.swift

@@ -1,11 +1,16 @@
 import RiveRuntime
 
 class HybridViewModelInstance: HybridViewModelInstanceSpec {
-  let viewModelInstance: RiveDataBindingViewModel.Instance
+  let viewModelInstance: RiveDataBindingViewModel.Instance?
 
   init(viewModelInstance: RiveDataBindingViewModel.Instance) {
     self.viewModelInstance = viewModelInstance
   }
 
+  override init() {
+    self.viewModelInstance = nil
+    super.init()
+  }
+  
   var name: String { "" }
 }