message: work for : fix getIncludedThemeCss
diff: @@ -275,12 +275,13 @@ export class StylesManager {
  .filter(themeName => ["defaultV2", "modern", "default"].indexOf(themeName) !== -1)
  .map(themeName => { return { name: themeName, theme: surveyCss[themeName] }; });
  - const res = [];
  if (!!document && !!document.body) {
  const styles = getComputedStyle(document.body);
  - res.push(themeMapper.filter(item => item.theme.variables && styles.getPropertyValue(item.theme.variables.themeMark))[0]);
  + if(styles.length) {
  + return themeMapper.filter(item => item.theme.variables && styles.getPropertyValue(item.theme.variables.themeMark));
  }
  - return res;
  + }
  + return [];
  }
  static findSheet(styleSheetId: string): any {
  