fix: don't barf with a null metaWindow

[mskorzhinskiy]

Using next-release branch of PaperWM-community on Gnome 40, I have noticed that some of the keybindings do not work for some reason. E.g. "Super+V", whic should open the calendar/notifications widget. Every hit of this keybinding additionally leads to a JS stack trace in the gnome journal.

This fix doesn't bring back the functionality, i.e. keybindigs are still not working (I know about Super+V and Super+S), but it removes the annoying stack trace.

Stack trace:

Dec 26 13:32:00 YogaTux gnome-shell[32061]: JS ERROR: TypeError: meta_window is null
                                            spaceOfWindow@/home/rasmi/.local/share/gnome-shell/extensions/paperwm@hedning:matrix.org/tiling.js:2136:9
                                            barf@/home/rasmi/.local/share/gnome-shell/extensions/paperwm@hedning:matrix.org/tiling.js:3274:24
                                            dynamic_function_ref/<@/home/rasmi/.local/share/gnome-shell/extensions/paperwm@hedning:matrix.org/utils.js:104:33
                                            asKeyHandler/<@/home/rasmi/.local/share/gnome-shell/extensions/paperwm@hedning:matrix.org/keybindings.js:268:20

[smichel17]

#27 (reply in thread)