BMFVerticalAlign constructor Null safety

1. flutter_baidu_mapapi_map
2. flutter_baidu_mapapi_map
3. BMFVerticalAlign
4. BMFVerticalAlign constructor

BMFVerticalAlign class

1. Constructors
2. BMFVerticalAlign
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Constants
12. ALIGN_BOTTOM
13. ALIGN_CENTER_VERTICAL
14. ALIGN_TOP