use primary key type for ActiveRecord::Calculations#ids return type

[ebarajas]

Motivation

This PR updates the built-in Tapioca::Dsl::Compilers::ActiveRecordRelations compiler to add a narrowed type for the return value of #ids. Before this was simply set to Array, so each item in the array was resolving to T.untyped.

Implementation

I duplicated some existing work done for the #find method to determine the type of the primary key column.

Tests

I've updated the existing test to assert the RBI is generated as expected.

[ebarajas]

I have signed the CLA!