feat(llc): add additional parameters to channel.truncate

packages/stream_chat/lib/src/core/api/channel_api.dart

@@ -265,10 +265,18 @@ class ChannelApi {
   /// Removes all messages from the channel
   Future<EmptyResponse> truncateChannel(
     String channelId,
-    String channelType,
-  ) async {
+    String channelType, {
+    Message? message,
+    bool? skipPush,
+    DateTime? truncatedAt,
+  }) async {
     final response = await _client.post(
       '${_getChannelUrl(channelId, channelType)}/truncate',
+      data: {
+        if (message != null) 'message': message,
+        if (skipPush != null) 'skip_push': skipPush,
+        if (truncatedAt != null) 'truncated_at': truncatedAt,
+      },
     );
     return EmptyResponse.fromJson(response.data);
   }