(Windows 10) Shortcuts that include Alt don't work properly.

### Bug description

If the shortcut includes Alt, it doesn't work properly. It just selects the menus at the top.

### Steps to reproduce

(An example)
1. Go to the shortcut settings in the Preferences, and assign Alt+A to Amplify feature.
2. Save the shortcut setting, and select a track.
3. Try to use the shortcut by pressing Alt+A.

### Expected behavior

It properly opens the Amplify feature.

### Actual behavior

It selects the Analyze menu at the top.

### Audacity Version

Audacity 4.0.0

### Operating system

Windows

### Additional context

_No response_

Start by reproducing the issue in the shortcut settings on Windows 10 with Alt+A assigned to Amplify, then trace the shortcut and menu handling involved. Done means Alt+A opens Amplify for a selected track instead of selecting the Analyze menu.

Written by the indexing model from the issue text.