clicks in panel and applets (e.g. workspace applet) cause app windows to lose focus

[jokeyrhyme]

Thanks so much for sharing this project, how exciting! <3

I did notice one issue in a mouse-driven work flow, to reproduce:

1. open cosmic-edit in workspace 1, click in it to ensure it has focus
2. use Super+2 to switch to workspace 2 and open cosmic-files there, click in it to ensure it has focus
3. use Super+1 and Super+2 to switch back and forth, and observe that both app windows have focus when their workspace is focused (as expected)
4. use the mouse to click on the "1" and "2" in the workspace applet to switch back and forth, and observe that neither app window has focus now (is this expected?)

• I think this is sort of related to Window loses focus when switching workspaces with super + shift + direction arrow cosmic-comp#439 but I reported it here because I think the solution could be implemented in or across a number of different components