thumbnail constant Null safety

1. wings_data_model
2. wings_data_model
3. MediaAssetFormatVariant
4. thumbnail constant

MediaAssetFormatVariant class

1. Properties
2. hashCode
3. name
4. runtimeType
5. Methods
6. noSuchMethod
7. toString
8. Operators
9. operator ==
10. Static properties
11. values
12. Static methods
13. valueOf
14. Constants
15. large
16. medium
17. small
18. thumbnail