NERtcVideoProfile constructor Null safety

1. yunxin_roomkit
2. roomkit
3. NERtcVideoProfile
4. NERtcVideoProfile constructor

NERtcVideoProfile class

1. Constructors
2. NERtcVideoProfile
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Constants
12. hd720p
13. hd1080p
14. low
15. standard