Empty arguments in tp.server.api.invoke call

[skrjanec]

Empty arguments in tp.server.api.invoke (UI framework) cause an unhandled error.

example:
tp.server.api.invoke({
name: this._queryApi
}).then(result => {
this.model.dataSources['versions'] = result;
section.activate();
this.element.querySelector('tp-floating-button').show();
});