nwg-shell-config 0.4.15

• removed unnecessary swaymsg reload in the default (Arch Linux) nwg-system-update script;
• "update-indicator-on" settings key set False in initial settings. As the appropriate form fields remain invisible if the program is running on a distribution that does not provide the nwg-system-update script, we need to leave if turned off by default. @mac-a-r0ni, @kuba3351 - this is the reason to update the nwg-shell-config version to 0.4.15 in what you're working on.