fix(tabs): delay loadView when animation runs (#8353)

* fix(tabs): delay loadView when animation runs

* chore: update api.md

* chore: remove unnecessary casting

* test: Added disabled test for changing tabs

nativescript-core/ui/frame/frame-common.ts

@@ -42,6 +42,7 @@ export class FrameBase extends CustomLayoutView implements FrameDefinition {
 
     public actionBarVisibility: "auto" | "never" | "always";
     public _currentEntry: BackstackEntry;
+    public _animationInProgress = false;
     public _executingContext: NavigationContext;
     public _isInFrameStack = false;
     public static defaultAnimatedNavigation = true;

nativescript-core/ui/frame/frame.d.ts

@@ -147,6 +147,10 @@ export class Frame extends View {
      * @private
      */
     navigationBarHeight: number;
+    /**
+     * @private
+     */
+    _animationInProgress: boolean;
     /**
      * @private
      */
@@ -218,21 +222,21 @@ export function setFragmentClass(clazz: any): void;
 
 /**
  * @deprecated Use Frame.getFrameById() instead.
- * 
+ *
  * Gets a frame by id.
  */
 export function getFrameById(id: string): Frame;
 
 /**
  * @deprecated Use Frame.topmost() instead.
- * 
+ *
  * Gets the topmost frame in the frames stack. An application will typically has one frame instance. Multiple frames handle nested (hierarchical) navigation scenarios.
  */
 export function topmost(): Frame;
 
 /**
  * @deprecated Use Frame.goBack() instead.
- * 
+ *
  * Navigates back using the navigation hierarchy (if any). Updates the Frame stack as needed.
  * This method will start from the topmost Frame and will recursively search for an instance that has the canGoBack operation available.
  */
@@ -241,7 +245,7 @@ export function goBack();
 //@private
 /**
  * @deprecated Use Frame._stack() instead.
- * 
+ *
  * @private
  */
 export function _stack(): Array<Frame>;
@@ -487,7 +491,7 @@ export function setActivityCallbacks(activity: any /*androidx.appcompat.app.AppC
 //@private
 /**
  * @deprecated Use Frame.reloadPage() instead.
- * 
+ *
  * @private
  */
 export function reloadPage(context?: ModuleContext): void;