fix(nav): prevents to remove all views in the nav stack

fixes #9140

src/navigation/nav-controller-base.ts

@@ -378,7 +378,7 @@ export class NavControllerBase extends Ion implements NavController {
       opts.direction = opts.direction || DIRECTION_BACK;
     }
 
-    const finalBalance = this._views.length + (insertViews ? insertViews.length : 0) - (destroyQueue ? destroyQueue.length : 0);
+    const finalBalance = this._views.length + (insertViews ? insertViews.length : 0) - (removeCount ? removeCount : 0);
     assert(finalBalance >= 0, 'final balance can not be negative');
     if (finalBalance === 0 && !this._isPortal) {
       console.warn(`You can't remove all the pages in the navigation stack. nav.pop() is probably called too many times.`,

src/navigation/test/view-controller.spec.ts

@@ -108,6 +108,7 @@ describe('ViewController', () => {
       // arrange
       let viewController = mockView();
       let navControllerBase = mockNavController();
+      navControllerBase._isPortal = true;
       mockViews(navControllerBase, [viewController]);
 
       viewController.onDidDismiss((data: any) => {
@@ -122,6 +123,7 @@ describe('ViewController', () => {
       // arrange
       let viewController = mockView();
       let navControllerBase = mockNavController();
+      navControllerBase._isPortal = true;
       mockViews(navControllerBase, [viewController]);
 
       viewController.onDidDismiss((data: any) => {

src/navigation/view-controller.ts

@@ -172,7 +172,7 @@ export class ViewController {
    * @returns {any} data Returns the data passed in, if any.
    *
    */
-  dismiss(data?: any, role?: any, navOptions: NavOptions = {}) {
+  dismiss(data?: any, role?: any, navOptions: NavOptions = {}): Promise<any> {
     if (!this._nav) {
       return Promise.resolve(false);
     }