fix(python): Enable manual commits for write_database with the ADBC engine

[mullimanko]

Closes #24558.

For example, this PR enables the to write to the database multiple times within the same transaction:

import adbc_driver_postgresql.dbapi as pg_dbapi
import polars as pl

conn_str ="postgresql://username:password@host:port/database"

df = pl.DataFrame({"a": [1], "b": [4]})

conn = pg_dbapi.connect(conn_str, autocommit=False)
print(f"Inspect autocommit status: {conn.adbc_connection.get_option("adbc.connection.autocommit")}")

df.write_database("public.table1", connection=conn, engine="adbc")
(df*2).write_database("public.table2", connection=conn, engine="adbc")
conn.commit()

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.74%. Comparing base (664656e) to head (252592c).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #24559      +/-   ##
==========================================
- Coverage   81.76%   81.74%   -0.02%     
==========================================
  Files        1684     1684              
  Lines      229458   229457       -1     
  Branches     2952     2952              
==========================================
- Hits       187616   187579      -37     
- Misses      41099    41135      +36     
  Partials      743      743              

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