fixed hanging chat when it contains any 'call'

lib/api/marianumcloud/talk/chat/getChatResponse.dart

@@ -121,4 +121,5 @@ enum RichObjectStringObjectType {
   @JsonValue('highlight') highlight,
   @JsonValue('talk-poll') talkPoll,
   @JsonValue('geo-location') geoLocation,
+  @JsonValue('call') call,
 }

lib/api/marianumcloud/talk/chat/getChatResponse.g.dart

@@ -117,4 +117,5 @@ const _$RichObjectStringObjectTypeEnumMap = {
   RichObjectStringObjectType.highlight: 'highlight',
   RichObjectStringObjectType.talkPoll: 'talk-poll',
   RichObjectStringObjectType.geoLocation: 'geo-location',
+  RichObjectStringObjectType.call: 'call',
 };