fix: prevent in & not in operators for relationship fields with hasMany: false

[PatrikKozak]

What?

This PR addresses a bug where relationship fields with hasMany: false (including polymorphic relationships) allowed filtering using the in and not in operators via the Admin UI, which led to query errors.

Why?

MongoDB & Postgres expect an array when using in & not in, but these fields return a single object (not an array).

How?

• in and not in operators are now excluded from the list of available filter operators for relationship fields where hasMany: false.

Fixes #12014

[tyteen4a03]

I don't think this behavior is correct.

I want to still be able to query many items based on the value of a relationship array (e.g. Item 1 with owner A, item 2 with owner B, item 3 with owner C. I should be able to specify where[owner.value][in]=A ). I think the solution here is instead making sure ins get turned into array of length 1 correctly.

[PatrikKozak]

@tyteen4a03 I see what you're saying and I agree. Noticing there are some discrepancies with using the in operator in general. I'm looking into it.