The question is asked immediately (or almost immediately, it might be the second screen) after the three screens that are used to collect the 1099-SA form's data entry.
To get back there, do a Search for "1099-sa" (lower case, without the double quotes), and jump to the result.
Click Edit at Your HSA Summary. When you get to the table of 1099-SAs (maybe just one), click on Edit for the appropriate 1099-SA (if more than one).
Go through (and after) the 3 1099-SA screens until you get to the one headed "Did you spend your HSA money on medical expenses only?"
