You mean "if a countable noun is two or more it is plural! We also usually use the plural with no.
She has no friends is the same as She doesn't have any friends. (Like the old song "Yes, we have no bananas".)
This Ngram shows that "...has no friend" was used more often in the past - but it is usually used when some description of the non-existent friend is added.
Poor Charles has no friend in the house.
He has no friend who is worthy of the name.