Unfortunately, you did not purchase the insurance you only added it to the reservation and it does not come into effect until after you pay the booking in full.
Bets t o call, there is a small chance that you can drop the friend and keep the same room. Alternatively Royal may insist that you move to a double occupancy room that will be priced at todays rates which you will then have to compare to what you paid which may be lower.
I would also check with AON (travelcruisecare.com) to see if one person can file a claim under the CFAR portion of the trip or whether it needs to be for the entire booking