perf(eval): optimize holidays collection and contains check in date functions

[PSU3D0]

Summary

• Optimize holiday collection from RangeView by iterating directly over non-null values in numbers_slices to avoid allocating LiteralValue cell elements.
• Sort and deduplicate the collected holidays once at the end of collection.
• Replace $O(H)$ linear .contains(&date) scans inside the date loops of NETWORKDAYS and WORKDAY (and their .INTL variants) with $O(\log H)$ binary searches.

Validation

• cargo fmt --all -- --check
• cargo test -p formualizer-eval --lib datetime::weekday_workday
• verified with new unit test networkdays_collects_sorted_deduped_holidays