Fix crash on calculating playlist duration when rate-changing mods are present

Regressed in https://github.com/ppy/osu/pull/28399.

To reproduce, enter a playlist that has an item with a rate-changing mod
(rather than create it yourself).

This is happening because `APIRuleset` has `CreateInstance()`
unimplemented:

    b4cefe0cc2/osu.Game/Online/API/Requests/Responses/APIBeatmap.cs (L159)

and only triggers when the playlist items in question originate from
web.

This is why it is bad to have interface implementations throw outside of
maybe mock implementations for tests. `CreateInstance()` is a scourge
elsewhere in general, we need way less of it in the codebase (because
while convenient, it's also problematic to implement in online contexts,
and also expensive because reflection).

osu.Game/Online/Rooms/PlaylistExtensions.cs

@@ -6,6 +6,7 @@ using System.Linq;
 using Humanizer;
 using Humanizer.Localisation;
 using osu.Framework.Bindables;
+using osu.Game.Rulesets;
 using osu.Game.Utils;
 
 namespace osu.Game.Online.Rooms
@@ -42,14 +43,14 @@ namespace osu.Game.Online.Rooms
         /// <summary>
         /// Returns the total duration from the <see cref="PlaylistItem"/> in playlist order from the supplied <paramref name="playlist"/>,
         /// </summary>
-        public static string GetTotalDuration(this BindableList<PlaylistItem> playlist) =>
+        public static string GetTotalDuration(this BindableList<PlaylistItem> playlist, RulesetStore rulesetStore) =>
             playlist.Select(p =>
             {
                 double rate = 1;
 
                 if (p.RequiredMods.Length > 0)
                 {
-                    var ruleset = p.Beatmap.Ruleset.CreateInstance();
+                    var ruleset = rulesetStore.GetRuleset(p.RulesetID)!.CreateInstance();
                     rate = ModUtils.CalculateRateWithMods(p.RequiredMods.Select(mod => mod.ToMod(ruleset)));
                 }
 

osu.Game/Screens/OnlinePlay/Components/OverlinedPlaylistHeader.cs

@@ -1,12 +1,17 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Allocation;
 using osu.Game.Online.Rooms;
+using osu.Game.Rulesets;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
     public partial class OverlinedPlaylistHeader : OverlinedHeader
     {
+        [Resolved]
+        private RulesetStore rulesets { get; set; } = null!;
+
         public OverlinedPlaylistHeader()
             : base("Playlist")
         {
@@ -16,7 +21,7 @@ namespace osu.Game.Screens.OnlinePlay.Components
         {
             base.LoadComplete();
 
-            Playlist.BindCollectionChanged((_, _) => Details.Value = Playlist.GetTotalDuration(), true);
+            Playlist.BindCollectionChanged((_, _) => Details.Value = Playlist.GetTotalDuration(rulesets), true);
         }
     }
 }

osu.Game/Screens/OnlinePlay/Playlists/PlaylistsRoomSettingsOverlay.cs

@@ -24,6 +24,7 @@ using osu.Game.Overlays;
 using osu.Game.Screens.OnlinePlay.Match.Components;
 using osuTK;
 using osu.Game.Localisation;
+using osu.Game.Rulesets;
 
 namespace osu.Game.Screens.OnlinePlay.Playlists
 {
@@ -78,6 +79,9 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
             [Resolved]
             private IAPIProvider api { get; set; } = null!;
 
+            [Resolved]
+            private RulesetStore rulesets { get; set; } = null!;
+
             private IBindable<APIUser> localUser = null!;
 
             private readonly Room room;
@@ -366,7 +370,7 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
             public void SelectBeatmap() => editPlaylistButton.TriggerClick();
 
             private void onPlaylistChanged(object? sender, NotifyCollectionChangedEventArgs e) =>
-                playlistLength.Text = $"Length: {Playlist.GetTotalDuration()}";
+                playlistLength.Text = $"Length: {Playlist.GetTotalDuration(rulesets)}";
 
             private bool hasValidSettings => RoomID.Value == null && NameField.Text.Length > 0 && Playlist.Count > 0
                                              && hasValidDuration;