Added option to add reactions to talk messages

lib/api/marianumcloud/talk/deleteReactMessage/deleteReactMessageParams.dart

@@ -0,0 +1,15 @@
+import 'package:json_annotation/json_annotation.dart';
+
+import '../../../apiParams.dart';
+
+part 'deleteReactMessageParams.g.dart';
+
+@JsonSerializable()
+class DeleteReactMessageParams extends ApiParams {
+  String reaction;
+
+  DeleteReactMessageParams(this.reaction);
+
+  factory DeleteReactMessageParams.fromJson(Map<String, dynamic> json) => _$DeleteReactMessageParamsFromJson(json);
+  Map<String, dynamic> toJson() => _$DeleteReactMessageParamsToJson(this);
+}