Is your feature request related to a problem or challenge?

Summary

Examples:

select array_union([1, 2, 3, 4], [5, 6, 3, 4]);
----
[1, 2, 3, 4, 5, 6]

select array_union([1, 2, 3, 4], [5, 6, 7, 8]);
----
[1, 2, 3, 4, 5, 6, 7, 8]

Describe the solution you'd like

No response

Describe alternatives you've considered

No response

Additional context

No response