feat(Android): opt-in to force dark

Author: vchimev

src/app-resources/_files/__name__/Android/values/styles.xml

@@ -21,6 +21,7 @@
 
     <!-- theme to use AFTER launch screen is loaded-->
     <style name="AppThemeBase" parent="Theme.AppCompat.Light.NoActionBar">
+        <item name="android:forceDarkAllowed">true</item>
         <item name="toolbarStyle">@style/NativeScriptToolbarStyle</item>
 
         <item name="colorPrimary">@color/ns_primary</item>