Update style for when the quick pick input is not enabled

Seems like we should be dimming the value text and setting the input use a `disabled` attribute to start. I assume we're showing progress via a notification or some other indicator? <img width="581" alt="CleanShot 2022-12-06 at 10 53 05@2x" src="https://user-images.githubusercontent.com/25163139/205997275-de7003cb-c1af-4fc3-b046-346b5dcfead6.png"> _Originally posted by @daviddossett in https://github.com/microsoft/vscode/issues/163753#issuecomment-1339828869_