This makes the `workspace_bar` more responsive to different child sizes, which enables fixing the size of the smaller dimension of the screencopy, while allowing it to expand unrestricted in the larger dimension (to match the aspect ratio).
This should probably be faster, but it's good for things like this to
not block the UI thread regardless.
We could probably also cache for multiple apps with the same ID. Not
sure if there's a good way to detect changes to the icon for an app id
(Not really needed, probably?)
