Add Support for arrayUnion Function

Why it matters

The arrayUnion function allows users to combine multiple arrays into one array containing unique elements only, eliminating duplicates. This feature simplifies array operations where deduplication of combined arrays is required, improving data processing efficiency and query clarity.

How to use it

Use the arrayUnion function by passing multiple array arguments to it in your queries. For example:

SELECT <code>arrayUnion</code>([1,2,3], [2,3,4]);

This returns an array with unique values combined from both arrays.