Update view.ts

In Angular you sometimes run into complete Flow Errors when Element was already unmounted and it ttries to unmount it again

packages/x6-angular-shape/src/view.ts

@@ -44,9 +44,9 @@ export class AngularShapeView extends NodeView<AngularShape> {
   }
 
   protected renderAngularContent(): void {
-    this.unmountAngularContent()
     const container = this.getNodeContainer()
     if (container) {
+      this.unmountAngularContent()
       const node = this.cell
       const { injector, content } = registerInfo.get(node.shape)!
       const viewContainerRef = injector.get(ViewContainerRef)