Convert uses of DirAccess * to DirAccessRef to prevent memleaks

`DirAccess *` needs to be deleted manually, and this is often forgotten
especially when doing early returns with `ERR_FAIL_COND`.
`DirAccessRef` is deleted automatically when it goes out of scope.

Co-authored-by: bruvzg <7645683+bruvzg@users.noreply.github.com>

scene/gui/file_dialog.h

@@ -70,7 +70,6 @@ private:
 
 	Button *makedir;
 	Access access = ACCESS_RESOURCES;
-	//Button *action;
 	VBoxContainer *vbox;
 	FileMode mode;
 	LineEdit *dir;