The `current-only` workspace setting should display only the active
workspace name as determined by its `focused` attribute. However,
according to the `get_tree` output, workspaces that contain a focused
window will report `"focused": false` and the window will report
`"focused": true.` In this case, Waybar will not display a workspace
name at all.
This change updates the logic for determining if a workspace is
focused by also looking for a focused window.
