fix: Decimal supertype for dyn int

[ritchie46]

fixes #16035

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 80.96%. Comparing base (0ed0e8a) to head (5c69546). Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #16046 +/- ## ======================================= Coverage 80.95% 80.96% ======================================= Files 1386 1386 Lines 178386 178385 -1 Branches 3064 3060 -4 ======================================= + Hits 144421 144423 +2 + Misses 33477 33472 -5 - Partials 488 490 +2 ``` | [Flag](https://app.codecov.io/gh/pola-rs/polars/pull/16046/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pola-rs) | Coverage Δ | | |---|---|---| | [python](https://app.codecov.io/gh/pola-rs/polars/pull/16046/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pola-rs) | `74.51% <100.00%> (+0.04%)` | :arrow_up: | | [rust](https://app.codecov.io/gh/pola-rs/polars/pull/16046/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pola-rs) | `78.14% <100.00%> (+<0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pola-rs#carryforward-flags-in-the-pull-request-comment) to find out more.

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[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #16046 will improve performances by 22.51%

_{Comparing decimal (5c69546) with main (fd0ae1d)}

Summary

⚡ 1 improvements ✅ 34 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	decimal	Change
⚡	test_filter2	2.7 ms	2.2 ms	+22.51%