fix(python, rust): use new schema for stats parsing instead of old

[ion-elgreco]

Description

In some edge cases where we schema evolve, it would parse the stats with the old schema result in these kind of errors:
Exception: Json error: whilst decoding field 'minValues': whilst decoding field 'foo': failed to parse 1000000000000 as Int8

import polars as pl
from deltalake import write_deltalake

pl.DataFrame({
    "foo": [1]
}, schema={"foo": pl.Int8}).write_delta("TEST_TABLE_BUG")


write_deltalake("TEST_TABLE_BUG", data = pl.DataFrame({
    "foo": [1000000000000]
}, schema={"foo": pl.Int64}).to_arrow(), mode='overwrite', overwrite_schema=True,engine='rust')

Instead of taking the old schema, I added an optional schema to be passed in the logMapper