fix: exclude :calculations from subquery select in wrap_in_subquery_for_aggregates

[jechol]

When wrap_in_subquery_for_aggregates tries to select :calculations from the subquery, it fails with:

** (Ecto.QueryError) field `calculations` in struct/2 is not available in the subquery. 
Subquery only returns fields: [...]

This fix filters out :calculations from select_calculations, keeping only the actual calculation columns (like __calculations____calc__0).

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[zachdaniel]

Hmm...in the case you're hitting, wouldn't this result in us missing calculations?

[zachdaniel]

What is the value of calculations there when you're hitting that case?

[zachdaniel]

@jechol any update here?

[jechol]

Hi, I just got time to work on this and created a minimal repro: https://github.com/jechol/ash_sql_load_sort_page_bug

Hope this helps with debugging!