test: assert ClickHouse overwrite SQL

[mday-io]

Description

Five ClickHouse overwrite tests compared generated SQL with expected statements without asserting the result, allowing incorrect replacement SQL to pass. Restore the assertions across full, time-range, key-based and partition-based overwrites, give staging and affected-partition tables distinct test names, and correct existing DISTINCT and cleanup expectations. Compare unordered partition actions without depending on Python hash order.

Three temporary mutations passed the original tests and failed the repaired assertions: a wrong exchange target, an inverted retained-row predicate, and a skipped incremental partition replacement.

Test Plan

• All 68 ClickHouse unit cases passed.
• The five repaired tests passed with PYTHONHASHSEED=1 and 42.
• All three mutations were rejected at the intended SQL assertions.
• make style passed after generating the worktree's ignored version module with setuptools-scm.
• make fast-test passed: 2,895 tests, 13 skipped across all required batches; 4 xdist workers.

Checklist

• I have run make style and fixed any issues
• I have added tests for my changes (if applicable)
• All existing tests pass (make fast-test)
• My commits are signed off (git commit -s) per the DCO