Added details for chats with participants list

lib/api/marianumcloud/talk/getParticipants/getParticipants.dart

@@ -0,0 +1,22 @@
+import 'dart:convert';
+
+import 'package:http/http.dart' as http;
+
+import '../talkApi.dart';
+import 'getParticipantsResponse.dart';
+
+class GetParticipants extends TalkApi<GetParticipantsResponse> {
+  String token;
+  GetParticipants(this.token) : super("v4/room/$token/participants", null);
+
+  @override
+  GetParticipantsResponse assemble(String raw) {
+    return GetParticipantsResponse.fromJson(jsonDecode(raw)['ocs']);
+  }
+
+  @override
+  Future<http.Response> request(Uri uri, Object? body, Map<String, String>? headers) {
+    return http.get(uri, headers: headers);
+  }
+
+}