Sway ipc fixes: wrong workspace highlighted with waybar

[TibboddiT]

I saw that #255 was closed, but I still experience this issue. In case it matters, I experienced it while launching miraclewm with WAYLAND_DISPLAY=wayland-98 miracle-wm

This PR fixes it.

AFAICT there were essentially 3 problems:

• old property on IPC_EVENT_WORKSPACE event with type focus was wrong
• set_is_active was not called on output after it was set to state.active_output
• focused was true for containers on not visible workspaces and false for all workspaces because root->is_focused() is always false

Feel free to not prioritize review/merge or to close this PR according to your current workload.

[mattkae]

Thanks for this fix! Do you think that you could re-merge develop onto you branch before I test it out? I just fixed waybar (again) and don't want anything that could mess it up