message: Change !question.value to isEmpty method
diff: @@ -68,14 +68,14 @@ export class SurveyQuestionFile extends SurveyQuestionElementBase {
  >
  {this.question.chooseButtonCaption}
  </label>
  - {this.question.isDisplayMode || !!this.question.value || (
  + {this.question.isDisplayMode || !this.question.isEmpty() || (
  <span className={this.question.cssClasses.noFileChosen}>
  {this.question.noFileChosenCaption}
  </span>
  )}
  </div>
  );
  - if (!!this.question.value && !this.isDisplayMode) {
  + if (!this.question.isEmpty() && !this.isDisplayMode) {
  clearButton = (
  <button
  type="button"
  