ci: set the right link to the Slack notification [skip ci]

[yshyn-iohk]

Small type fix

Checklist:

• My PR follows the contribution guidelines of this project
• My PR is free of third-party dependencies that don't comply with the Allowlist
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have checked the PR title to follow the conventional commit specification

[github-actions]

Integration Test Results

 5 files  ±0   5 suites  ±0   12s ⏱️ -1s
17 tests ±0  17 ✅ ±0  0 💤 ±0  0 ❌ ±0 
20 runs  ±0  20 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit 5986ed4. ± Comparison against base commit 6a28ef8.