Master effect stack does not update for undo and redo

### Bug description

_No response_

### Steps to reproduce

1. make a rhythm track
2. Open the History view non-modal dialog
3. Add built-in reverb to the master stack
4. Play; hear reverb
5. Undo
6. Observe correct update in the History dialog. But...

### Expected behavior

After 6, the side bar should show an empty master stack, and playback should not have reverb

### Actual behavior

Still hear reverb; still see it in the stack

### Audacity Version

current master / alpha / nightly build

### Operating system

Windows, macOS, Linux

### Additional context

Sorry, my fault. RealtimeEffectList::RestoreUndoRedoState is not a correct implementation. Tags was the wrong analogy.

It should be redone analogously to TrackList Restorer, as a separate object, which holds a complete snapshot of the realtime effect stack's state by copying it completely.

Start by inspecting RealtimeEffectList::RestoreUndoRedoState and compare it with the TrackList Restorer, as suggested in the issue. Reproduce the undo step with a master reverb effect and verify that undo and redo update both the sidebar stack and playback behavior.

Written by the indexing model from the issue text.