Use persons' first names for mock data to reduce chance of conflicts

Vehicle models seems to have a high enough probability that it sometimes
fails

tests/Vegasco.Server.Api.Tests.Integration/CarFaker.cs

@@ -9,11 +9,11 @@ internal class CarFaker
 
 	internal CreateCar.Request CreateCarRequest()
 	{
-		return new CreateCar.Request(_faker.Vehicle.Model());
+		return new CreateCar.Request(_faker.Person.FirstName);
 	}
 
 	internal UpdateCar.Request UpdateCarRequest()
 	{
-		return new UpdateCar.Request(_faker.Vehicle.Model());
+		return new UpdateCar.Request(_faker.Person.FirstName);
 	}
 }