NERtcVideoOutputOrientationMode constructor Null safety

1. nertc
2. nertc
3. NERtcVideoOutputOrientationMode
4. NERtcVideoOutputOrientationMode constructor

NERtcVideoOutputOrientationMode class

1. Constructors
2. NERtcVideoOutputOrientationMode
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Constants
12. adaptative
13. fixedLandscape
14. fixedPortrait