Use getDisplayMetrics().

`getRealMetrics()` is now deprecated as well. It suggests using `getCurrentWindowMetrics()` instead, but that's new in SDK 30 and doesn't even contain DPI information. Whereas this function has been around since the start.

templates/android/template/app/src/main/java/org/haxe/lime/GameActivity.java

@@ -37,8 +37,7 @@ public class GameActivity extends SDLActivity {
 
 		if (metrics == null) {
 
-			metrics = new DisplayMetrics ();
-			Extension.mainActivity.getWindowManager ().getDefaultDisplay ().getRealMetrics (metrics);
+			metrics = Extension.mainContext.getResources ().getDisplayMetrics ();
 
 		}