Move `optimize_subquery_sort` into optimizer as a new rule `EliminateSort`

I have no idea why we have optimize plan rule `optimize_subquery_sort` in `create_relation`, I think we should move such rule to optimizer 🤔

_Originally posted by @jayzhan211 in https://github.com/apache/datafusion/pull/15300#discussion_r2002212215_

Locate optimize_subquery_sort in create_relation and inspect the optimizer rules to understand where the proposed EliminateSort rule belongs. Move the rule into the optimizer as EliminateSort, then verify the existing query-planning tests still pass and that the subquery sort optimization remains covered.

Written by the indexing model from the issue text.