settings [nfc]: Drop return value from updateGlobalSettings

We don't currently end up using this anywhere.

Author: gnprice

lib/model/store.dart

@@ -64,14 +64,13 @@ abstract class GlobalStore extends ChangeNotifier {
   GlobalSettingsData get globalSettings => _globalSettings;
   GlobalSettingsData _globalSettings;
 
-  /// Update the global settings in the store, returning the new version.
+  /// Update the global settings in the store.
   ///
   /// The global settings must already exist in the store.
-  Future<GlobalSettingsData> updateGlobalSettings(GlobalSettingsCompanion data) async {
+  Future<void> updateGlobalSettings(GlobalSettingsCompanion data) async {
     await doUpdateGlobalSettings(data);
     _globalSettings = _globalSettings.copyWithCompanion(data);
     notifyListeners();
-    return _globalSettings;
   }
 
   /// Update the global settings in the underlying data store.

test/model/store_test.dart

@@ -37,10 +37,9 @@ void main() {
       final globalStore = eg.globalStore();
       check(globalStore).globalSettings.themeSetting.equals(null);
 
-      final result = await globalStore.updateGlobalSettings(
+      await globalStore.updateGlobalSettings(
         GlobalSettingsCompanion(themeSetting: Value(ThemeSetting.dark)));
       check(globalStore).globalSettings.themeSetting.equals(ThemeSetting.dark);
-      check(result).equals(globalStore.globalSettings);
     });
 
     test('should notify listeners', () async {