fix(notification_indicator): adjust indicator position and remove redundant code

- Update NotificationIndicator to use Positioned.directional for better alignment
- Remove redundant Directionality widget in discover_sliver_app_bar.dart and feed_sliver_app_bar.dart
- Adjust positioning values for the indicator in notification_indicator.dart

Author: fulleni

lib/discover/widgets/discover_sliver_app_bar.dart

@@ -79,16 +79,13 @@ class DiscoverSliverAppBar extends StatelessWidget
                 child: BlocSelector<AppBloc, AppState, bool>(
                   selector: (state) => state.hasUnreadInAppNotifications,
                   builder: (context, showIndicator) {
-                    return Directionality(
-                      textDirection: Directionality.of(context),
-                      child: NotificationIndicator(
-                        showIndicator: showIndicator,
-                        child: BlocSelector<AppBloc, AppState, User?>(
-                          selector: (state) => state.user,
-                          builder: (context, user) {
-                            return UserAvatar(user: user);
-                          },
-                        ),
+                    return NotificationIndicator(
+                      showIndicator: showIndicator,
+                      child: BlocSelector<AppBloc, AppState, User?>(
+                        selector: (state) => state.user,
+                        builder: (context, user) {
+                          return UserAvatar(user: user);
+                        },
                       ),
                     );
                   },

lib/headlines-feed/widgets/feed_sliver_app_bar.dart

@@ -85,16 +85,13 @@ class FeedSliverAppBar extends StatelessWidget implements PreferredSizeWidget {
                 child: BlocSelector<AppBloc, AppState, bool>(
                   selector: (state) => state.hasUnreadInAppNotifications,
                   builder: (context, showIndicator) {
-                    return Directionality(
-                      textDirection: Directionality.of(context),
-                      child: NotificationIndicator(
-                        showIndicator: showIndicator,
-                        child: BlocSelector<AppBloc, AppState, User?>(
-                          selector: (state) => state.user,
-                          builder: (context, user) {
-                            return UserAvatar(user: user);
-                          },
-                        ),
+                    return NotificationIndicator(
+                      showIndicator: showIndicator,
+                      child: BlocSelector<AppBloc, AppState, User?>(
+                        selector: (state) => state.user,
+                        builder: (context, user) {
+                          return UserAvatar(user: user);
+                        },
                       ),
                     );
                   },

lib/shared/widgets/notification_indicator.dart

@@ -27,9 +27,10 @@ class NotificationIndicator extends StatelessWidget {
       children: [
         child,
         if (showIndicator)
-          Positioned(
-            top: 0,
-            right: 0,
+          Positioned.directional(
+            textDirection: Directionality.of(context),
+            top: 2,
+            end: 2,
             child: Container(
               width: AppSpacing.sm,
               height: AppSpacing.sm,