Testing: add reporting failed tests to GHA summary

[Yury-Fridlyand]

See how it is done in C# client: valkey-io/valkey-glide-csharp#41

Applicable to all other clients. This simplifies failure analysis and debugging.
Test suite should hook/subscribe to events of failed test and log them in MD format into a file which name stored in $GITHUB_STEP_SUMMARY. Logged entries should contain permalink to the failed test if possible.