Bulk Ingestion into Postgresql Numeric with scale

### What would you like help with?

Env:
- Macos Sonoma (14.5)
- Python 3.11.9
- pyarrow 17.0.0
- adbc_driver_postgresql 1.2.0

Background:
I want to load data into Postgresql using Bulk Ingestion/Copy command from parquet file.
I have pyarrow "amount" column with pa.float64(), to be inserted into Numeric with scale column in Postgresql "amount numeric(18, 2)".

Then I got this error below:
`Exception: ProgrammingError('INVALID_ARGUMENT: [libpq] Failed to execute COPY statement: PGRES_FATAL_ERROR ERROR: insufficient data left in message\nCONTEXT: COPY invoice_new, line 1, column amount\n. SQLSTATE: 08P01')`

And I tried to change pyarrow schema "amount" column into "decimal256(18, 2)"
I got this error below:
`Exception: ProgrammingError('INVALID_ARGUMENT: [libpq] Failed to execute COPY statement: PGRES_FATAL_ERROR ERROR: invalid scale in external "numeric" value\nCONTEXT: COPY invoice_new, line 1, column amount\n. SQLSTATE: 22P03')`

To fix this error, do I need cast pyarrow "amount" column schema to another schema type?

Ty