_everyFormElementHas(property) {
      return Object.keys(this.formElements).every(name => {
        if (Array.isArray(this.formElements[name])) {
          return this.formElements[name].every((/** @type {FormControl} */ el) => !!el[property]);
        }
        return !!this.formElements[name][property];
      });
    }
Returns true when all of the formElements have requested property
@param {string} property