fix Response.render

[artem-burlakov-ext-orion]

before:

render(locals = {}, template = this.templateName) {
    this.responseType = 'rendering';
    // FIXME: check if property already exists
    Object.assign(this.locals, locals);
    this.templateName = template;
  }

after:

render(locals = {}, template = this.templateName) {
    this.responseType = 'rendering';
    const self = this;
    Object.entries(locals).forEach(([key, value]) => self.addLocal(key, value));
    this.templateName = template;
  }