Add more unit tests for event_handlers

[3vilhamster]

What changed?
Added a couple of unit tests for internal event_handlers and removed unused method.

Why?
Improving code coverage to be above the bar.

How did you test it?

Potential risks

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.52%. Comparing base (06afa1f) to head (045df16).
Report is 1 commits behind head on master.

Files with missing lines	Coverage Δ
internal/internal_event_handlers.go	70.94% <ø> (+3.25%)	⬆️

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 06afa1f...045df16. Read the comment docs.

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests