cs_startup: fix custom commands with spaces in path (#13229)

Automatically add quotes if selected filepath contains spaces.

fixes linuxmint/cinnamon-settings-daemon#363

Author: okaestne

files/usr/share/cinnamon/cinnamon-settings/modules/cs_startup.py

@@ -899,6 +899,8 @@ def on_browse_button_clicked(self, button):
 
         if response == Gtk.ResponseType.ACCEPT:
             name = chooser.get_filename()
+            if " " in name:
+                name = '"' + name + '"'
             self.command_entry.set_text(name)
 
         chooser.destroy()