Not only does this combine the check into one location, but it also adds
a check on the global `WorkingBeatmap` being updated, which is the only
way I can see the following failure happening:
```csharp
05:19:07 osu.Game.Tests: osu.Game.Tests.Visual.Editing.TestSceneEditorBeatmapCreation.TestAddAudioTrack
05:19:07 Failed TestAddAudioTrack [161 ms]
05:19:07 Error Message:
05:19:07 TearDown : System.NullReferenceException : Object reference not set to an instance of an object.
05:19:07 Stack Trace:
05:19:07 --TearDown
05:19:07 at osu.Game.Database.ModelManager`1.<>c__DisplayClass7_0.<AddFile>b__0(TModel managed) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\ModelManager.cs:line 36
05:19:07 at osu.Game.Database.ModelManager`1.<>c__DisplayClass8_0.<performFileOperation>b__0(Realm realm) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\ModelManager.cs:line 49
05:19:07 at osu.Game.Database.RealmExtensions.Write(Realm realm, Action`1 function) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\RealmExtensions.cs:line 14
05:19:07 at osu.Game.Database.ModelManager`1.performFileOperation(TModel item, Action`1 operation) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\ModelManager.cs:line 46
05:19:07 at osu.Game.Database.ModelManager`1.AddFile(TModel item, Stream contents, String filename) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Database\ModelManager.cs:line 36
05:19:07 at osu.Game.Screens.Edit.Setup.ResourcesSection.ChangeAudioTrack(FileInfo source) in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Screens\Edit\Setup\ResourcesSection.cs:line 115
05:19:07 at osu.Game.Tests.Visual.Editing.TestSceneEditorBeatmapCreation.<TestAddAudioTrack>b__13_0() in C:\BuildAgent\work\ecd860037212ac52\osu.Game.Tests\Visual\Editing\TestSceneEditorBeatmapCreation.cs:line 101
05:19:07 at osu.Framework.Testing.Drawables.Steps.AssertButton.checkAssert()
05:19:07 at osu.Framework.Testing.Drawables.Steps.StepButton.PerformStep(Boolean userTriggered)
05:19:07 at osu.Framework.Testing.TestScene.runNextStep(Action onCompletion, Action`1 onError, Func`2 stopCondition)
```
The whole component is pointless so I'm just going to nuke for now I
guess. Kind of makes the whole refactor effort pointless but oh well?
To expand on this, the implementation was actually incorrect as pointed
out at https://github.com/ppy/osu/pull/18819#pullrequestreview-1017886035.
Previously, all control points would get replaced, which led to
performance issues that was worked around in this PR. By comparing
control points, we're able to get good performance without requiring the
workaround.
