currentThemeMode property Null safety

Implementation

ThemeMode get currentThemeMode {
  if (_userPreferences.currentTheme == THEME_SYSTEM_DEFAULT) {
    return ThemeMode.system;
  } else if (_userPreferences.currentTheme == THEME_LIGHT) {
    return ThemeMode.light;
  } else {
    return ThemeMode.dark;
  }
}