style(spacing): adjust spacing between title and About icon

- Change SizedBox width from AppSpacing.sm to AppSpacing.xs in multiple files:
  - app_configuration_page.dart
  - content_management_page.dart
  - settings_page.dart

Author: fulleni

lib/app_configuration/view/app_configuration_page.dart

@@ -52,7 +52,7 @@ class _AppConfigurationPageState extends State<AppConfigurationPage>
               l10n.appConfigurationPageTitle,
             ),
             const SizedBox(
-              width: AppSpacing.sm,
+              width: AppSpacing.xs,
             ),
             AboutIcon(
               dialogTitle: l10n.appConfigurationPageTitle,

lib/content_management/view/content_management_page.dart

@@ -183,7 +183,7 @@ class _ContentManagementPageState extends State<ContentManagementPage>
             children: [
               Text(l10n.contentManagement),
               const SizedBox(
-                width: AppSpacing.sm,
+                width: AppSpacing.xs,
               ),
               AboutIcon(
                 dialogTitle: l10n.contentManagement,

lib/settings/view/settings_page.dart

@@ -65,7 +65,7 @@ class _SettingsViewState extends State<_SettingsView> {
           children: [
             Text(l10n.settings),
             const SizedBox(
-              width: AppSpacing.sm,
+              width: AppSpacing.xs,
             ),
             AboutIcon(
               dialogTitle: l10n.settings,