Use @vue/test-utils for tooltip_on_truncate_spec

What does this MR do?

Updates tooltip_on_truncate_spec to use @vue/test-utils.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content