Revert "Move break cloning back to non-virtual method"

This reverts commit f69bc40a4b.

osu.Game/Beatmaps/BeatmapConverter.cs

@@ -49,8 +49,6 @@ namespace osu.Game.Beatmaps
             // Can potentially be removed after `Beatmap.Difficulty` doesn't save back to `Beatmap.BeatmapInfo`.
             original.BeatmapInfo = original.BeatmapInfo.Clone();
             original.ControlPointInfo = original.ControlPointInfo.DeepClone();
-            // Used in osu!mania conversion.
-            original.Breaks = new List<BreakPeriod>(original.Breaks);
 
             return ConvertBeatmap(original, cancellationToken);
         }
@@ -68,6 +66,8 @@ namespace osu.Game.Beatmaps
             beatmap.BeatmapInfo = original.BeatmapInfo;
             beatmap.ControlPointInfo = original.ControlPointInfo;
             beatmap.HitObjects = convertHitObjects(original.HitObjects, original, cancellationToken).OrderBy(s => s.StartTime).ToList();
+            // Used in osu!mania conversion.
+            beatmap.Breaks = new List<BreakPeriod>(original.Breaks);
             beatmap.UnhandledEventLines = original.UnhandledEventLines;
 
             return beatmap;