fix: Cleanup worker event handling

[bmingles]

• Remove event handler when query is running or fails
• Handle failed query starts and cleanup

resolves #158

[github-actions[bot]]

End-to-end Test Summary

Tests 📝	Passed ✅	Failed ❌	Skipped ⏭️	Pending ⏳	Other ❓	Flaky 🍂	Duration ⏱️
6	6	0	0	0	0	0	05:01:55

A ctrf plugin

Detailed Test Results

Name	Status	ms	Flaky 🍂
should default to the correct settings	passed ✅	1919
should return custom settings: Empty configs	passed ✅	257
should return custom settings: Populated configs	passed ✅	106
should be able to load VSCode	passed ✅	989
should only be visible when a supported file type is active: test.groovy	passed ✅	2885
should only be visible when a supported file type is active: test.py	passed ✅	1113

A ctrf plugin

Failed Test Summary

No failed tests ✨

Flaky Test Summary

No flaky tests detected. ✨