chore: remove critical circular dependencies (#8114)

* chore: remove critical circular dependencies

* chore: fix tslint errors

* chore: remove platform specific types from interfaces

* chore: update unit tests polyfills

* fix: incorrect null check

* chore: update api.md file

* test: improve test case

* chore: apply comments

* test: avoid page style leaks in tests

nativescript-core/application/application-interfaces.ts

@@ -0,0 +1,79 @@
+// Types
+import { EventData } from "../data/observable/observable-interfaces";
+import { View } from "../ui/core/view";
+
+export interface ApplicationEventData extends EventData {
+    ios?: any;
+    android?: any;
+    eventName: string;
+    object: any;
+}
+
+export interface LaunchEventData extends ApplicationEventData {
+    root?: View;
+    savedInstanceState?: any /* android.os.Bundle */;
+}
+
+export interface OrientationChangedEventData extends ApplicationEventData {
+    newValue: "portrait" | "landscape" | "unknown";
+}
+
+export interface SystemAppearanceChangedEventData extends ApplicationEventData {
+    newValue: "light" | "dark";
+}
+
+export interface UnhandledErrorEventData extends ApplicationEventData {
+    ios?: NativeScriptError;
+    android?: NativeScriptError;
+    error: NativeScriptError;
+}
+
+export interface DiscardedErrorEventData extends ApplicationEventData {
+    error: NativeScriptError;
+}
+
+export interface CssChangedEventData extends EventData {
+    cssFile?: string;
+    cssText?: string;
+}
+
+export interface AndroidActivityEventData {
+    activity: any /* androidx.appcompat.app.AppCompatActivity */;
+    eventName: string;
+    object: any;
+}
+
+export interface AndroidActivityBundleEventData extends AndroidActivityEventData {
+    bundle: any /* android.os.Bundle */;
+}
+
+export interface AndroidActivityRequestPermissionsEventData extends AndroidActivityEventData {
+    requestCode: number;
+    permissions: Array<string>;
+    grantResults: Array<number>;
+}
+
+export interface AndroidActivityResultEventData extends AndroidActivityEventData {
+    requestCode: number;
+    resultCode: number;
+    intent: any /* android.content.Intent */;
+}
+
+export interface AndroidActivityNewIntentEventData extends AndroidActivityEventData {
+    intent: any /* android.content.Intent */;
+}
+
+export interface AndroidActivityBackPressedEventData extends AndroidActivityEventData {
+    cancel: boolean;
+}
+
+/**
+* @deprecated
+*/
+export interface RootViewControllerImpl {
+    contentController: any;
+}
+
+export interface LoadAppCSSEventData extends EventData {
+    cssFile: string;
+}