feat: Remove .env file for AI Scribe

It was used at the beginning for configuration purpose but now we
have the JMAP capability, no need anymore.

test/features/composer/presentation/composer_controller_test.dart

@@ -8,7 +8,6 @@ import 'package:core/utils/application_manager.dart';
 import 'package:core/utils/platform_info.dart';
 import 'package:dartz/dartz.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter_dotenv/flutter_dotenv.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:get/get.dart';
 import 'package:html_editor_enhanced/html_editor.dart';
@@ -241,11 +240,6 @@ void main() {
   setUp(() {
     Get.testMode = true;
 
-    // Initialize DotEnv for testing
-    dotenv.testLoad(mergeWith: {
-      'AI_ENABLED': 'false',
-    });
-
     // Mock base controller
     mockCachingManager = MockCachingManager();
     mockLanguageCacheManager = MockLanguageCacheManager();