fix(account): update icon for empty followed countries list

- Replace Icons.public_off_outlined with Icons.location_off_outlined
- Improve visual consistency with more specific location-related icon

Author: fulleni

lib/account/view/manage_followed_items/countries/followed_countries_list_page.dart

@@ -63,7 +63,7 @@ class FollowedCountriesListPage extends StatelessWidget {
 
           if (followedCountries.isEmpty) {
             return InitialStateWidget(
-              icon: Icons.public_off_outlined,
+              icon: Icons.location_off_outlined,
               headline: l10n.followedCountriesEmptyHeadline,
               subheadline: l10n.followedCountriesEmptySubheadline,
             );