id property Null safety

1. Figma2flutter
2. figma2flutter
3. Elem
4. id property

Elem class

1. Constructors
2. Elem
3. Properties
4. componentName
5. hashCode
6. id
7. name
8. pageName
9. painter
10. runtimeType
11. type
12. widget
13. Methods
14. noSuchMethod
15. toString
16. Operators
17. operator ==