put the faster check first in App.isInstalled()

A > is much faster than all the stuff that isMediaInstalled() has to do,
so put > first, so that if it is true, isMediaInstalled() is not executed.

app/src/main/java/org/fdroid/fdroid/data/App.java

@@ -856,7 +856,7 @@ public class App extends ValueObject implements Comparable<App>, Parcelable {
     }
 
     public boolean isInstalled(Context context) {
-        return isMediaInstalled(context) || installedVersionCode > 0;
+        return installedVersionCode > 0 || isMediaInstalled(context);
     }
 
     public boolean isMediaInstalled(Context context) {