Fix reading_pictographs_2 to deal with the new randRangeUnique()

See b10ef1d1cedad80e5869ab06fdf495d8f635cf17

Test plan: Before the change, load reading_pictographs_2 in local/debug mode, refresh until DATA contained an 8. Note horrible breakage. After this change, do the same thing and note that DATA works if it contains 7 and that's the largest it seems to pick.

Auditors: alpert