Grade 6 in German grade system counts as 5.67 (6+) when calculating average

[SaMaili]

General Troubleshooting

• [x] I have checked for similar issues.
• [x] I have updated to the latest version.
• [x] I have checked the branches or the maintainers' PRs for upcoming fixes.

Describe the bug Grade 6 in German grade system counts as 5.67 when calculating the average of grades. The app thinks it exists the grade 6+.

It should be a fast fix

Environment:

• Device model:
• OS version:
• App version:

[SaMaili]