launchEvent is not triggered at the same moment on iOS and Android.
iOS is firing after setting the rootView while Android is firing before.
Consequently if you need an event for when the rootView is set (to read/write root css variables) you need this event.
[skip ci]
NativeScriptError type def used to come from packages/core/global-types.d.ts now comes from packages/core/application/application-interfaces.ts, so fixed there now.
BREAKING CHANGES:
`Application.orientation` is no longer a function.
Migration: Remove `()` from the `Application.orientation()` call:
```diff
import { Application } from "@nativescript/core";
-console.log(Application.orientation());
+console.log(Application.orientation);
```
`Application.systemAppearance` is no longer a function.
Migration: Remove `()` from the `Application.systemAppearance()` call:
```diff
import { Application } from "@nativescript/core";
-console.log(Application.systemAppearance());
+console.log(Application.systemAppearance);
```
