🐛 Bug Report: realtimeMessage.fromMap crashes with _Map<String, dynamic> is not a subtype of Iterable<dynamic>

### 👟 Reproduction steps

1. Set up an Appwrite Realtime subscription on a collection/document channel (e.g., messaging).
2. Trigger a document creation event (e.g., send a message that creates a document in the subscribed collection).
3. The Realtime WebSocket receives the event of type `"event"`.
4. The SDK attempts to parse the incoming event data via `RealtimeMessage.fromMap()`.
5. The app crashes with an unhandled exception.

### 👍 Expected behavior

The `RealtimeMessage.fromMap()` factory constructor should correctly parse the incoming WebSocket event data regardless of whether the server sends `events` or `channels` as a `List` or a `Map`. The Realtime subscription callback should fire with a valid `RealtimeMessage` object containing the event payload.

### 👎 Actual Behavior

```
E/flutter (16642): [ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: type '_Map' is not a subtype of type 'Iterable'
E/flutter (16642): #0 new RealtimeMessage.fromMap (package:appwrite/src/realtime_message.dart:57:47)
E/flutter (16642): #1 RealtimeMixin._createSocket. (package:appwrite/src/realtime_mixin.dart:100:45)
E/flutter (16642): #2 _RootZone.runUnaryGuarded (dart:async/zone.dart:1778:10)
...
```

### 🎲 Appwrite version

Version 2.0.x

### 💻 Operating system

Windows

### 🧱 Your Environment

Flutter app using BLoC pattern for state management
Appwrite Realtime subscriptions on tablesdb/tables channels
Standard Appwrite Cloud

### 👀 Have you spent some time to check if this issue has been raised before?

- [x] I checked and didn't find similar issue

### 🏢 Have you read the Code of Conduct?

- [x] I have read the [Code of Conduct](https://github.com/appwrite/appwrite/blob/HEAD/CODE_OF_CONDUCT.md)