onTapNo property Null safety

1. farmershands
2. popup_screen
3. PopupScreen
4. onTapNo property

PopupScreen class

1. Constructors
2. PopupScreen
3. Properties
4. child
5. data
6. hashCode
7. key
8. onClose
9. onTapCancel
10. onTapNo
11. onTapNormal
12. onTapOutside
13. onTapYes
14. padding
15. runtimeType
16. type
17. Methods
18. createElement
19. createState
20. debugDescribeChildren
21. debugFillProperties
22. noSuchMethod
23. toDiagnosticsNode
24. toString
25. toStringDeep
26. toStringShallow
27. toStringShort
28. Operators
29. operator ==
30. Constants
31. routeName