DataFrame.to_dicts change str values

[lizeyan]

Checks

• I have checked that this issue has not already been reported.
• I have confirmed this bug exists on the latest version of Polars.

Reproducible example

import polars as pl
print(pl.from_dicts([{"A": "0.1"}]).to_dicts())

Log output

[{'A': '0'}]

Issue description

The str value changed

Expected behavior

[{'A': '0.1'}]

Installed versions

--------Version info---------
Polars:              1.8.1
Index type:          UInt32
Platform:            macOS-14.0-arm64-arm-64bit
Python:              3.12.6 (main, Sep 20 2024, 16:43:14) [Clang 15.0.0 (clang-1500.3.9.4)]

----Optional dependencies----
adbc_driver_manager  <not installed>
altair               <not installed>
cloudpickle          <not installed>
connectorx           <not installed>
deltalake            <not installed>
fastexcel            <not installed>
fsspec               <not installed>
gevent               <not installed>
great_tables         <not installed>
matplotlib           <not installed>
nest_asyncio         <not installed>
numpy                2.1.1
openpyxl             <not installed>
pandas               <not installed>
pyarrow              <not installed>
pydantic             <not installed>
pyiceberg            <not installed>
sqlalchemy           <not installed>
torch                <not installed>
xlsx2csv             <not installed>
xlsxwriter           <not installed>

[rodrigogiraoserrao]

(On polars 1.7.1 I didn't get the bug but I also get it on 1.8.1.)

[lizeyan]

(On polars 1.7.1 I didn't get the bug but I also get it on 1.8.1.)

Yes. It reproduces on 1.8.0 and 1.8.1. On 1.7.1 it is OK.

[coastalwhite]

Bisect shows that it started in #18664. Will look at it.