The onDismissProgrammatic function bound to the DropdownAlert component cannot be triggered, which is the same as that of iOS/Android

[Panlichen1996]

DropdownAlert 组件绑定的onDismissProgrammatic 函数无法触发，与iOS/Android一致 复现问题的demo

alertProps: {
        onDismissProgrammatic: () => {
          _onDismissTypeChange('onDismissProgrammatic');
        },
        alertPosition: 'bottom',
      }