Sample edit mode pencil flickers when hovering

### Bug description

The change from the text cursor to the pencil cursor when editing samples flickers briefly before appearing.

### Steps to reproduce

1. Enter sample editing mode (zoom in)
2. Hover and approach with your cursor
3. Observe the change from the text cursor to the pencil cursor

### Expected behavior

Smooth transition as with the other cursors

### Actual behavior

An enlargened, pixel-spaced version of the pencil appears briefly before the correctly sized pencil appears.

### Audacity Version

Audacity Development 4.0.0, build: 252910310,

### Operating system

Windows

### Additional context

The phantom utensil could not be captured using screenrecording software. This may indicate at which layer of the software stack the issue is introduced. Here's a video shot on my cell phone: https://immich.kdb424.xyz/share/eHtSXNSdu2upYi_7w7juSKiWASLFhTr0ctStxu9nq-YJ46TmiR_KbdXXSJkDeGgXCZ0