Fall back to using APIUser.Statistics for rank in UserPanel (#37717)

Fixes friend list not showing global rank of the users.
I think #37709 can be closed without any further client-side changes
after `osu-web` is made to return global rank on user searches.

osu.Game/Users/UserPanel.cs

@@ -141,7 +141,7 @@ namespace osu.Game.Users
             // We can't colour the properly because we don't have the required percentile data.
 
             Colour = Colours.BlueLighter,
-            Text = User.Rank?.Rank?.ToLocalisableString("\\##,##0") ?? string.Empty,
+            Text = (User.Rank?.Rank ?? User.Statistics.GlobalRank)?.ToLocalisableString("\\##,##0") ?? string.Empty,
         };
 
         protected UpdateableAvatar CreateAvatar() => new UpdateableAvatar(User, false);