Allow mapping arbitrary IEnumerables to arrays

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#29427 is enabling primitive collection support in EF, and we're implementing that via PostgreSQL arrays. Arrays have been supported in the PG provider for a long while, but was restricted to arrays and List<T>. Since it has been decided on the EF side that we should allow mapping any IEnumerable to a primitive collection in the database, the same should be done on the PG side as well.

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@AndriySvyryd I opened this on this repo by mistake, this is PG work that shouldn't require anything from core. Opened npgsql/efcore.pg#2726 on the PG side for this.