Oh, they told you that because they didn't know what else to say.
I don't think there's anything in the law about that.
You could have your dd take a standardized test, and if she scores at least at the grade level she just completed, that should be proof that she "passed." There are many places you can order such tests; one of them is Bayside School Services.
Or you can order a report card from Rainbow Resources, fill it out for the last quarter of school, and indicate that she is promoted to the next grade. https://www.rainbowresource.com/product/sku/025265