They say you are an Agent of the Dealership.
Sorry, but in the vehicle sales business, there are no “agents” of dealerships.
There are owners, salespeople, service managers, service techs, finance managers. All except the owner require a salesperson license.
If you are selling a car that is in the name of a dealer, you are an employee by law. You may be a contract sales employee (1099) or a direct employee (W-2).
In all cases you are a salesperson which will require a sales license in California.