added specieskey to make class reflection in Calculations.class stronger

src/main/java/com/pfefferminzia/petinsurance/calculations/Calculations.java

@@ -23,8 +23,7 @@ public class Calculations {
         TariffOption tariff =
                 tariffConfig.getTariffFactor(contract.tariffName(), insuranceStartDate);
 
-        String speciesKey = animal.getClass().getSimpleName().toUpperCase();
-        BigDecimal baseInsuranceSum = tariffConfig.getAnimalBaseSum(speciesKey);
+        BigDecimal baseInsuranceSum = tariffConfig.getAnimalBaseSum(animal.speciesKey());
 
         BigDecimal insuranceSum = getInsuranceSum(baseInsuranceSum, tariff.factor());