drive: fix missing files when using --fast-list and --drive-shared-with-me

This bug was introduced here by removing some necessary code detecting
shared with me items at the root with no parents.

4453fa4ba6 "drive: fix --fast-list when using appDataFolder"

This fix reverts that part of the patch.

Fixes #4018

backend/drive/drive.go

@@ -1591,6 +1591,10 @@ func (f *Fs) listRRunner(ctx context.Context, wg *sync.WaitGroup, in <-chan list
 		listRSlices{dirs, paths}.Sort()
 		var iErr error
 		_, err := f.list(ctx, dirs, "", false, false, false, func(item *drive.File) bool {
+			// shared with me items have no parents when at the root
+			if f.opt.SharedWithMe && len(item.Parents) == 0 && len(paths) == 1 && paths[0] == "" {
+				item.Parents = dirs
+			}
 			for _, parent := range item.Parents {
 				var i int
 				// If only one item in paths then no need to search for the ID