hasAllFilesAccess method
Returns true when the app can enumerate arbitrary directories on
external storage. On Android 11+ this means the "All Files Access"
(MANAGE_EXTERNAL_STORAGE) special access setting; it is always true on
Android 10 and below and on iOS / macOS.
Implementation
Future<bool> hasAllFilesAccess() =>
throw UnimplementedError('hasAllFilesAccess() not implemented.');