Memory pointer from external source (e.g, FFI) is not aligned for empty list[str]

[ion-elgreco]

Describe the bug
Can't consume arrow data with empty list[str] over FFI

To Reproduce

import polars as pl
from arro3.core import Table
df = pl.DataFrame(
    {
        "bar": [[]],
    }, schema={"bar": pl.List(pl.String)}
)

Table(df)

Expected behavior
Pyarrow seems to be able to consume this empty list[str] fine,

import polars as pl
import pyarrow as pa
df = pl.DataFrame(
    {
        "bar": [[]],
    }, schema={"bar": pl.List(pl.String)}
)

pa.table(df)

Additional context
Created also issue in polars repo: pola-rs/polars#22935, since it's not clear to me where the issue lies, wether it's polars buffers being misaligned or arrow-rs incorrectly identifying it because pyarrow seems to be able to consume it fine.

[viirya]

I reproduced the reported issue locally with a arro3 test case to arro3 repo.

Proposed #8009 as a fix. I verified that after applying the patch, the Python test case can run without issue.