Remove enter on begin of warnign message
Closes #57082

With current code, it is not possible to filter pandas warning about PyArrow that leads to crash of test suite with the rule to treat warning as error. 

It looks like the source of the problem is that `warnigns` library compile pattern with only IgnoreCase flag.

https://github.com/python/cpython/blob/d1b031cc58516e1aba823fd613528417a996f50d/Lib/warnings.py#L160

And then is using `match` instead of `search` so it matches to initial line. 

With this change, it this warning will be possible to ignore this using:

```
"ignore:Pyarrow will become a required dependency of pandas in the next major release of pandas.*:DeprecationWarning"
```

In napari we meet it here: https://github.com/napari/napari/pull/6609

cPython issue about problem with empty line https://github.com/python/cpython/issues/114426
Numpy failure looks unrelated  Let's hold on this for now, since we might just revert the deprecation entirely for 2.2.1. Please consider my comment for the PR, thanks.
https://github.com/pandas-dev/pandas/issues/57082#issuecomment-1935291850
 Thanks for the start here but the warning ended up getting removed in https://github.com/pandas-dev/pandas/pull/57556 so closing