Plugin Duplicate entries in Preferences -> Shortcuts

### Bug description

Plugins have duplicate entries in Preferences -> Shortcuts

### Steps to reproduce

1. Launch Audacity 4
2. Go to Preferences
3. Go to Shortcuts
4. Observe duplicate plugin entries

### Expected behavior

There should be no duplicate plugin entries in Shortcuts menu

### Actual behavior

There are duplicate plugin entries in Shortcuts menu

### Audacity Version

cc81882b80a5b46315493e7bbe21af06100694e9

### Operating system

OS independent

### Additional context