fix(user): Replace cubit context read with state variable on login page

lib/ui/pages/setup/initializing.dart

@@ -418,6 +418,14 @@ class InitializingPage extends StatelessWidget {
                   'initializing.enter_nickname_and_password'.tr(),
                 ),
                 const Spacer(),
+                if (formCubitState.isErrorShown)
+                          Text(
+                            'users.username_rule'.tr(),
+                            style: TextStyle(
+                              color: Theme.of(context).colorScheme.error,
+                            ),
+                          ),
+                const SizedBox(height: 10),   
                 CubitFormTextField(
                   formFieldCubit: context.read<RootUserFormCubit>().userName,
                   textAlign: TextAlign.center,

lib/ui/pages/users/new_user.dart

@@ -55,7 +55,7 @@ class NewUser extends StatelessWidget {
                     child: Column(
                       mainAxisSize: MainAxisSize.min,
                       children: [
-                        if (context.read<UserFormCubit>().state.isErrorShown)
+                        if (formCubitState.isErrorShown)
                           Text(
                             'users.username_rule'.tr(),
                             style: TextStyle(