getBody method Null safety

Implementation

@override
List<Widget> getBody() => <Widget>[
      _getListTile(
        title: appLocalizations.instagram,
        url: 'https://instagram.com/open.food.facts',
      ),
      _getListTile(
        title: appLocalizations.twitter,
        url: 'https://www.twitter.com/openfoodfacts',
      ),
      _getListTile(
        title: appLocalizations.blog,
        url: 'https://en.blog.openfoodfacts.org',
      ),
      _getListTile(
        title: appLocalizations.support_join_slack,
        url: 'https://slack.openfoodfacts.org/',
      ),
      _getListTile(
        title: appLocalizations.support_via_email,
        onTap: () async {
          final PackageInfo packageInfo = await PackageInfo.fromPlatform();
          final Mailto mailtoLink = Mailto(
            to: <String>['contact@openfoodfacts.org'],
// This shouldn't be translated as its a debug message to OpenFoodFacts
            subject: 'Smoothie help',
            body:
                'Version:${packageInfo.version}+${packageInfo.buildNumber} running on ${Platform.operatingSystem}(${Platform.operatingSystemVersion})',
          );
          await launchUrl(Uri.parse('$mailtoLink'));
        },
      ),
    ];