use night drawable variants instead of getting category icons programatically

Signed-off-by: Harry Bond <me@hbond.xyz>

android/app/src/main/java/app/organicmaps/search/CategoriesAdapter.java

@@ -110,10 +110,7 @@ class CategoriesAdapter extends RecyclerView.Adapter<CategoriesAdapter.ViewHolde
                                            @NonNull String packageName,
                                            @NonNull String key)
   {
-    final boolean isNightTheme = ThemeUtils.isNightTheme(context);
     String iconId = "ic_" + key;
-    if (isNightTheme)
-      iconId = iconId + "_night";
     return context.getResources().getIdentifier(iconId, "drawable", packageName);
   }