Why my bottom sheet has an awkward white space at the top? Flutter

Question

I am trying to make my ListView of items inside my bottom sheet scrollable. I make it work with DraggableScrollableSheet widget but there's this awkward white space. Can someone review my code and tell me what's wrong?

onPressed: () {
    showModalBottomSheet(
      isDismissible: true,
      isScrollControlled: true,
      context: context,
      shape: const RoundedRectangleBorder(
          borderRadius: const BorderRadius.vertical(
        top: Radius.circular(20),
      )),
      builder: (context) => DraggableScrollableSheet(
initialChildSize: 0.7,
minChildSize: 0.2,
maxChildSize: 0.75,
builder: (_, controller) => Container(
        padding: const EdgeInsets.all(16),
        child: ListView(
          children: [
            Image.network(
              imageURl,
              loadingBuilder: (context, child, loadingProgress) {
                if (loadingProgress == null) return child;
                return const CircularProgressIndicator();
              },
              errorBuilder: (context, error, stackTrace) =>
                  Text(errorMessage),
            ),
            ListTile(
              title: Text(
                information1,
                textAlign: TextAlign.justify,
              ),
            ),
            ListTile(
              title: Text(
                information2,
                textAlign: TextAlign.justify,
              ),
            ),
            Padding(
              padding: const EdgeInsets.all(10.0),
              child: Container(
                child: CupertinoButton.filled(
                  padding: EdgeInsets.all(15),
                  child: Text(information3),
                  onPressed: () async {
                    if (await canLaunch(linkURl)) {
                      await launch(
                        linkURl,
                        universalLinksOnly: true,
                      );
                    } else {
                      throw 'There was a problem to open the url.';
                    }
                  },
                ),
              ),
            ),
          ],
        ),
      ),
    ),
    );
  },

Sample on how it works:

As you can seen in the above video, there is an awkward white space on top of the image. What's causing it and how do I get rid of it?

Thanks!