test(iam): fix tests crashing in case of get api-key failure

[estellesoulard]

Following this failed job: https://github.com/scaleway/scaleway-cli/actions/runs/18701945888/job/53332405971#step:4:62

• fix panic happening outside of test function context

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 56.33%. Comparing base (3ec89ce) to head (998a367).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@ Coverage Diff @@ ## master #5075 +/- ## ======================================= Coverage 56.33% 56.33% ======================================= Files 307 307 Lines 78498 78498 ======================================= Hits 44219 44219 Misses 32845 32845 Partials 1434 1434 

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.