Refactor: Update enforce_sorting tests to use insta snapshots for easier updates (#17900)

* Refactor: Update enforce_sorting tests to use insta snapshots for easier updates

* port some more

* fmt

* Cleanup representation

* migrate `test_sort_merge_join_order_by_left`

* migrate `test_sort_merge_join_order_by_right`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* migrate `test_with_lost_ordering_unbounded_bounded`

Split the rstest parameterized test into two separate functions:
- test_with_lost_ordering_unbounded
- test_with_lost_ordering_bounded

Each tests both repartition_sorts modes (false and true) using insta snapshots.
Replaced the incomplete existing test_with_lost_ordering_bounded which only
tested one mode.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* Start migrating `test_window_partial_constant_and_set_monotonicity`

* Migrate the rest `test_window_partial_constant_and_set_monotonicity`

* Clippy

* Kill `expect_no_change` (we now have `Input / Optimized Plan` unification)

* Fmt

* Merge more plans with the same before and output

* Kill `expected_description`

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Co-authored-by: blaginin <[email protected]>
Co-authored-by: Claude <[email protected]>

Author: 3 people