chore(modal-navigation-ng): add tests for nested modal views without frames

Author: ADjenkov

Diff for: e2e/modal-navigation-ng/app/modal/modal.component.html

@@ -6,7 +6,7 @@
     <StackLayout backgroundColor="lightGreen">
         <Button text="Navigate To Second Page" (tap)="onNavigateSecondPage()" [visibility]="navigationVisibility"></Button>
         <Button text="Show Nested Modal Page With Frame" (tap)="showNestedModalFrame()" [visibility]="navigationVisibility"></Button>
-        <Button text="Show Nested Modal Page" (tap)="showNestedModal()" [visibility]="navigationVisibility"></Button>
+        <Button text="Show Nested Modal Page" (tap)="showNestedModal()"></Button>
         <Button text="Show Dialog" (tap)="showDialogConfirm()"></Button>
         <Button text="Close Modal" (tap)="close(rootLayout)"></Button>
     </StackLayout>

Diff for: e2e/modal-navigation-ng/e2e/modal-layout.e2e-spec.ts

@@ -45,6 +45,10 @@ describe("modal-layout:", () => {
                 await screen.loadedHome();
             });
 
+            it("should show nested modal page, run in background, close", async () => {
+                await testNestedModalPageBackground(driver, screen, false);
+            });
+
             it("should show dialog confirm inside modal view with no frame, run in background", async () => {
                 await testDialogBackground(driver, screen, false);
             });

Diff for: nativescript-angular/directives/dialogs.ts

@@ -67,6 +67,9 @@ export class ModalDialogService {
             parentView = parentView.ngAppRoot;
         }
 
+        // _ngDialogRoot is the first child of the previously detached proxy.
+        // It should have 'viewController' (iOS) or '_dialogFragment' (Android) available for
+        // presenting future modal views.
         if (parentView._ngDialogRoot) {
             parentView = parentView._ngDialogRoot;
         }