fix: JOIN-34406 handle duplication slug error during event type update

[dmkav]

What does this PR do?

Fixes # (issue)

Environment: Staging(main branch) / Production

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Chore (refactoring code, technical debt, workflow improvements)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How should this be tested?

• Test A
• Test B

Checklist

• I haven't read the contributing guide
• My code doesn't follow the style guidelines of this project
• I haven't performed a self-review of my own code and corrected any misspellings
• I haven't commented my code, particularly in hard-to-understand areas
• I haven't checked if my PR needs changes to the documentation
• I haven't checked if my changes generate no new warnings
• I haven't added tests that prove my fix is effective or that my feature works
• I haven't checked if new and existing unit tests pass locally with my changes

[pavnaumenko]

@dmkav did you check the error handling on FE part? Does it display the proper tooltip or component with a correct message to the end user with a new error type?