update worker:fatalError event description

[seralexeev]

Description

Fixed the incorrect description for the worker:fatalError event in src/interfaces.ts.

Performance impact

None - this is a documentation-only change (fixing a comment).

Security impact

None - this is a documentation-only change (fixing a comment).

Checklist

• My code matches the project's code style and yarn lint:fix passes.
• I've added tests for the new feature, and yarn test passes.
• I have detailed the new feature in the relevant documentation.
• I have added this feature to 'Pending' in the RELEASE_NOTES.md file (if one exists).
• If this is a breaking change I've explained why.