Guard against use of sync_local_library when the user is not logged in.

Let's not take an exception for this. It happens on each Lutris startup, if you aren't logged in already.

lutris/gui/lutriswindow.py

@@ -237,10 +237,10 @@ class LutrisWindow(Gtk.ApplicationWindow, DialogLaunchUIDelegate, DialogInstallU
             if value.accel:
                 app.add_accelerator(value.accel, "win." + name)
 
-    def sync_library(self):
+    def sync_library(self, force=False):
         """Tasks that can be run after the UI has been initialized."""
         if settings.read_setting("library_sync_enabled"):
-            AsyncCall(sync_local_library, None)
+            AsyncCall(sync_local_library, None, force=force)
 
     def update_action_state(self):
         """This invokes the functions to update the enabled states of all the actions
@@ -844,8 +844,7 @@ class LutrisWindow(Gtk.ApplicationWindow, DialogLaunchUIDelegate, DialogInstallU
         return True
 
     def on_lutris_account_connected(self):
-        if settings.read_bool_setting("library_sync_enabled"):
-            AsyncCall(sync_local_library, None, force=True)
+        self.sync_library(force=True)
 
     def on_local_library_updated(self):
         self.redraw_view()

lutris/util/library_sync.py

@@ -54,6 +54,9 @@ def sync_local_library(force: bool = False) -> None:
     local_library = get_local_library()
     local_library_updates = get_local_library(since=since)
     credentials = read_api_key()
+    if not credentials:
+        return
+
     url = LIBRARY_URL
     if since:
         url += "?since=%s" % since