feat: Converted to ios models

packages/stream_chat/lib/src/models/event.dart

@@ -171,15 +171,15 @@ class EventChannel extends ChannelModel {
     this.members,
     String? id,
     String? type,
-    String? cid,
-    ChannelConfig? config,
+    required String cid,
+    required ChannelConfig config,
     User? createdBy,
-    bool? frozen,
+    bool frozen = false,
     DateTime? lastMessageAt,
-    DateTime? createdAt,
-    DateTime? updatedAt,
+    required DateTime createdAt,
+    required DateTime updatedAt,
     DateTime? deletedAt,
-    int? memberCount,
+    required int memberCount,
     Map<String, dynamic>? extraData,
   }) : super(
           id: id,