Factory method for displaying twemojis with Unicode Strings

We want to keep our emoji list in our backend
So it is safer to keep them in their unicode strings.
Currently there is no way to display them using unicode strings.
Can you please add a method for this?
```
            Twemoji(
              emojiUnicode: "1F355",  //NEW
              fit: BoxFit.scaleDown,
              height: 20,
            ),
```