chore: remove multilingual language model

lib/pangea/learning_settings/models/language_model.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/material.dart';
 
-import 'package:fluffychat/l10n/l10n.dart';
 import 'package:fluffychat/pangea/learning_settings/constants/language_constants.dart';
 import 'package:fluffychat/pangea/learning_settings/enums/l2_support_enum.dart';
 
@@ -60,13 +59,6 @@ class LanguageModel {
         displayName: "Unknown",
       );
 
-  static LanguageModel multiLingual([BuildContext? context]) => LanguageModel(
-        displayName: context != null
-            ? L10n.of(context).multiLingualSpace
-            : "Multilingual Space",
-        langCode: LanguageKeys.multiLanguage,
-      );
-
   String? getDisplayName(BuildContext context) {
     return displayName;
   }

lib/pangea/learning_settings/utils/p_language_store.dart

@@ -42,7 +42,6 @@ class PLanguageStore {
       _langList = _langList.toSet().toList();
 
       _langList.sort((a, b) => a.displayName.compareTo(b.displayName));
-      _langList.insert(0, LanguageModel.multiLingual());
     } catch (err, stack) {
       debugger(when: kDebugMode);
       ErrorHandler.logError(

lib/pangea/learning_settings/widgets/p_language_dropdown.dart

@@ -14,7 +14,6 @@ class PLanguageDropdown extends StatefulWidget {
   final List<LanguageModel> languages;
   final LanguageModel? initialLanguage;
   final Function(LanguageModel) onChange;
-  final bool showMultilingual;
   final bool isL2List;
   final String? decorationText;
   final String? error;
@@ -28,7 +27,6 @@ class PLanguageDropdown extends StatefulWidget {
     required this.languages,
     required this.onChange,
     required this.initialLanguage,
-    this.showMultilingual = false,
     this.decorationText,
     this.isL2List = false,
     this.error,
@@ -132,15 +130,6 @@ class PLanguageDropdownState extends State<PLanguageDropdown> {
             ),
           ),
           items: [
-            if (widget.showMultilingual)
-              DropdownMenuItem(
-                value: LanguageModel.multiLingual(context),
-                enabled: widget.enabled,
-                child: LanguageDropDownEntry(
-                  languageModel: LanguageModel.multiLingual(context),
-                  isL2List: widget.isL2List,
-                ),
-              ),
             ...sortedLanguages.map(
               (languageModel) => DropdownMenuItem(
                 value: languageModel,