Describe the bug
Previously, pressing a on a multi-select gum choose prompt would select all items.
This behaviour was broken in 0.14, I'm assuming because of this PR: #521

To Reproduce
Steps to reproduce the behavior:

1. Run gum choose --no-limit x y z
2. Press a
3. Nothing happens

Expected behavior

1. Run gum choose --no-limit x y z
2. Press a
3. All items are selected

Screenshots
N/A

Desktop:

• OS: Pop!OS 22.04 (based on Ubuntu 22.04)
• Gum 0.14.0