refactor(web): remove unused splash screen remover code

- Remove unused import for WebSplashRemover
- Remove post-frame callback for removing splash screen on web

Author: fulleni

lib/main.dart

@@ -2,7 +2,6 @@ import 'package:device_preview/device_preview.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_news_app_mobile_client_full_source_code/app/config/config.dart';
-import 'package:flutter_news_app_mobile_client_full_source_code/app/services/splash_screen_remover/web_splash_remover.dart';
 import 'package:flutter_news_app_mobile_client_full_source_code/bootstrap.dart';
 
 // Define the current application environment (production/development/demo).
@@ -17,13 +16,6 @@ void main() async {
 
   final appWidget = await bootstrap(appConfig, appEnvironment);
 
-  // Only remove the splash screen on web after the app is ready.
-  if (kIsWeb) {
-    WidgetsBinding.instance.addPostFrameCallback((_) {
-      removeSplashFromWeb();
-    });
-  }
-
   if (appConfig.environment == AppEnvironment.demo && kIsWeb) {
     runApp(
       DevicePreview(