Indexing error on exams/schedule card

[DGoiana]

Closes #1531

Review checklist

• Terms and conditions reflect the current change
• Contains enough appropriate tests
• If aimed at production, writes a new summary in whatsnew/whatsnew-pt-PT
• Properly adds an entry in changelog.md with the change
• If PR includes UI updates/additions, its description has screenshots
• Behavior is as expected
• Clean, well-structured code

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 9%. Comparing base (a6ccef5) to head (17ec671).

❌ Your project check has failed because the head coverage (9%) is below the target coverage (70%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff             @@
##           ui/redesign   #1551   +/-   ##
===========================================
  Coverage            9%      9%           
===========================================
  Files              259     259           
  Lines             7429    7429           
===========================================
  Hits               650     650           
  Misses            6779    6779           

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