Update walletkit/flutter/eip5792.mdx

Co-authored-by: Jakub Witczak <jakubwitczak6@gmail.com>

Author: rohit-710

walletkit/flutter/eip5792.mdx

@@ -219,7 +219,7 @@ This capability is expressed per chain and is crucial for determining how `walle
     ```dart
     final Map<String, dynamic> scopedProperties = {
       'eip155': WalletKit.buildWalletService(
-        'https://wallet-service-url.com',
+        "${bundler_url}",
         ['wallet_getCallsStatus'],
       ),
     };