Exercises G26

Description: When level 15 is reached the diamonds from the completed challenges are not added to the total diamond number calculated from the start of the game

Steps to reproduce:
1. Start the game with an account level 15
2. Check the total number of diamonds
3. Complete a challenge
4. Check the total number of diamonds

Expected result: The total number of diamonds before completing the challenge should be one less than the number of diamonds after completing the challenge

Actual result: When reaching level 15 the total number of diamonds is the same before and after completing a challenge