Does this issue occur when all extensions are disabled?: Yes/No

• VS Code Version: 1.105.1
• OS Version: MacOS 26.1

Steps to Reproduce:
As a theme developer for VSCode I want to highlight the install button separate from other buttons in the view, however currently setting the extensionButton.prominentBackground color property does nothing. After investigating, the extensionButton.prominentBackground is getting overridden by extensionButton.background