I wouldn’t be happy with that and I’d want all four tyres to be the same on a new car.
I wonder if the dealer swapped the wheel with one off another car for whatever reason, rather than change the tyre - could be that one of your car’s wheels was damaged while the car was in transit between the factory and your dealer, so they swapped the complete wheel and tyre. If they have changed the tyre, rather than swapping the wheel, I’d check the wheel with the Pirelli tyre very carefully to see if there’s any damage to it that might have been caused by fitting a replacement tyre. Also, are you able to see any sticky residue on the barrel of the wheel where the original wheel balance weights have been removed and new ones fitted as a result of it needing to be rebalanced? - a good indication that the tyre’s been changed.
I’d certainly be asking the dealer for an explanation. If the dealer agrees to fit a new Continental tyre (as they should do) to match the others, get them to agree the condition of the wheel before they change the tyre - take photos of the wheel so you can prove what it’s condition is before they change the tyre. There’s lots of mentions on various forums of diamond cut alloy wheels being damaged by poorly maintained tyre fitting equipment and poorly trained or careless technicians.
And if they damage the wheel changing the tyre, demand a new wheel!