BUG: rounding datetime in series is broken

Pandas version checks

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Reproducible Example

pd.Series([pd.to_datetime("2022-01-09T12:00:01")]).round("30min") == pd.Series([pd.to_datetime("2022-01-09T12:00:01").round("30min")])

Issue Description

Repeat of issue of #57002

Expected Behavior

example should return true

Installed Versions

INSTALLED VERSIONS ------------------ commit : d9cdd2ee5a58015ef6f4d15c7226110c9aab8140 python : 3.10.13.final.0 python-bits : 64 OS : Linux OS-release : 5.15.153.1-microsoft-standard-WSL2 Version : #1 SMP Fri Mar 29 23:14:13 UTC 2024 machine : x86_64 processor : byteorder : little LC_ALL : None LANG : en_US.UTF-8 LOCALE : en_US.UTF-8 pandas : 2.2.2 numpy : 1.26.4 pytz : 2024.1 dateutil : 2.9.0 setuptools : 69.1.0 pip : 24.0 Cython : None pytest : 8.1.1 hypothesis : None sphinx : None blosc : None feather : None

pandas-dev / pandas