[BUG] Non-solo clips play for a split second

### Bug description

When a track has been set as solo (S button), playing over another track will make it make an audible sound for a split second

### Steps to reproduce

1. Create two tracks, A and B
2. Set A to solo
3. Go over a clip in B
4. Hit play

### Expected behavior

B should remain muted

### Actual behavior

The clip from B can be heard for a split second

### Audacity Version

Audacity 4.0 beta 2

### Operating system

Linux

### Additional context

Bug occurs both on the JACK and ALSA backends, cannot test on Windows unfortunately

No source file or test is identified in the issue. Reproduce the two-track case on Linux with both JACK and ALSA, then trace playback startup and solo/mute handling to find where the non-solo clip becomes audible; done means track B produces no sound at any point while A is solo.

Written by the indexing model from the issue text.