refactor(ui): Make users be ordered properly on users page

- Resolves https://git.selfprivacy.org/SelfPrivacy/selfprivacy.org.app/issues/340

lib/logic/cubit/users/users_state.dart

@@ -18,6 +18,32 @@ class UsersState extends ServerInstallationDependendState {
   @override
   List<Object> get props => [users, isLoading];
 
+  /// Makes a copy of existing users list, but places 'primary'
+  /// to the beginning and sorts the rest alphabetically
+  ///
+  /// If found a 'root' user, it doesn't get copied into the result
+  List<User> get orderedUsers {
+    User? primaryUser;
+    final List<User> normalUsers = [];
+    for (final User user in users) {
+      if (user.type == UserType.primary) {
+        primaryUser = user;
+        continue;
+      }
+      if (user.type == UserType.root) {
+        continue;
+      }
+      normalUsers.add(user);
+    }
+
+    normalUsers.sort(
+      (final User a, final User b) =>
+          a.login.toLowerCase().compareTo(b.login.toLowerCase()),
+    );
+
+    return primaryUser == null ? normalUsers : [primaryUser] + normalUsers;
+  }
+
   UsersState copyWith({
     final List<User>? users,
     final bool? isLoading,

lib/ui/pages/users/user.dart

@@ -3,11 +3,11 @@ part of 'users.dart';
 class _User extends StatelessWidget {
   const _User({
     required this.user,
-    required this.isRootUser,
+    required this.isUserPrimary,
   });
 
   final User user;
-  final bool isRootUser;
+  final bool isUserPrimary;
   @override
   Widget build(final BuildContext context) => InkWell(
         onTap: () {
@@ -32,7 +32,7 @@ class _User extends StatelessWidget {
                   user.login,
                   style: Theme.of(context).textTheme.titleMedium?.copyWith(
                         color: Theme.of(context).colorScheme.onBackground,
-                        decoration: isRootUser
+                        decoration: isUserPrimary
                             ? TextDecoration.underline
                             : user.isFoundOnServer
                                 ? TextDecoration.none

lib/ui/pages/users/users.dart

@@ -45,15 +45,7 @@ class UsersPage extends StatelessWidget {
     } else {
       child = BlocBuilder<UsersCubit, UsersState>(
         builder: (final BuildContext context, final UsersState state) {
-          final List<User> users = state.users
+          final users = state.orderedUsers;
-              .where((final user) => user.type != UserType.root)
-              .toList();
-          // final List<User> users = [];
-          users.sort(
-            (final User a, final User b) =>
-                a.login.toLowerCase().compareTo(b.login.toLowerCase()),
-          );
-
           if (users.isEmpty) {
             if (state.isLoading) {
               return const Center(
@@ -115,7 +107,7 @@ class UsersPage extends StatelessWidget {
                     itemBuilder:
                         (final BuildContext context, final int index) => _User(
                       user: users[index],
-                      isRootUser: users[index].type == UserType.primary,
+                      isUserPrimary: users[index].type == UserType.primary,
                     ),
                   ),
                 ),