style(content_management): adjust padding for filter pages

- Change padding from all sides to only top
- Update applied for headlines_page.dart, sources_page.dart, and topics_page.dart
- Adjust padding value from AppSpacing.lg to AppSpacing.sm

Author: fulleni

lib/content_management/view/headlines_page.dart

@@ -51,7 +51,7 @@ class _HeadlinesPageState extends State<HeadlinesPage> {
   Widget build(BuildContext context) {
     final l10n = AppLocalizationsX(context).l10n;
     return Padding(
-      padding: const EdgeInsets.all(AppSpacing.lg),
+      padding: const EdgeInsets.only(top: AppSpacing.sm),
       child: BlocBuilder<ContentManagementBloc, ContentManagementState>(
         builder: (context, state) {
           final headlinesFilterState = context

lib/content_management/view/sources_page.dart

@@ -52,7 +52,7 @@ class _SourcesPageState extends State<SourcesPage> {
   Widget build(BuildContext context) {
     final l10n = AppLocalizationsX(context).l10n;
     return Padding(
-      padding: const EdgeInsets.all(AppSpacing.lg),
+      padding: const EdgeInsets.only(top: AppSpacing.sm),
       child: BlocBuilder<ContentManagementBloc, ContentManagementState>(
         builder: (context, state) {
           final sourcesFilterState = context.watch<SourcesFilterBloc>().state;

lib/content_management/view/topics_page.dart

@@ -48,7 +48,7 @@ class _TopicPageState extends State<TopicPage> {
   Widget build(BuildContext context) {
     final l10n = AppLocalizationsX(context).l10n;
     return Padding(
-      padding: const EdgeInsets.all(AppSpacing.lg),
+      padding: const EdgeInsets.only(top: AppSpacing.sm),
       child: BlocBuilder<ContentManagementBloc, ContentManagementState>(
         builder: (context, state) {
           final topicsFilterState = context.watch<TopicsFilterBloc>().state;