ios 按需导入头文件

两个项目同时引用了 flutter_absolute_path，但是其中一个import <flutter_absolute_path-Swift.h>报错，另一个#import <flutter_absolute_path/flutter_absolute_path-Swift.h>报错，使用一个最简单的办法解决：

#if __has_include(<flutter_absolute_path/flutter_absolute_path-Swift.h>)
#import <flutter_absolute_path/flutter_absolute_path-Swift.h>
#else
#import <flutter_absolute_path-Swift.h>
#endif