.cursor() loses schema information

### What happens?

Whenever .cursor is called the description says `Create a duplicate of the current connection` however it actually losses the relevant schema information and instead switches to main

### To Reproduce

```python3
con = duckdb.connect()
con.execute("CREATE SCHEMA IF NOT EXISTS other_schema")
con.execute("USE other_schema")
print(con.cursor().execute("SELECT current_schema()").fetchone())
```

### OS:

Linux x86_64

### DuckDB Package Version:

1.4.0

### Python Version:

3.11.9

### Full Name:

Julian Meyers

### Affiliation:

Independent

### What is the latest build you tested with? If possible, we recommend testing with the latest nightly build.

I have not tested with any build

### Did you include all relevant data sets for reproducing the issue?

Not applicable - the reproduction does not require a data set

### Did you include all code required to reproduce the issue?

- [x] Yes, I have

### Did you include all relevant configuration to reproduce the issue?

- [x] Yes, I have

まず、報告された Python の再現を DuckDB Python package に対して実行し、connection.cursor() の実装とテストを調べます。カーソルの作成時にアクティブなスキーマがどのように扱われるかを追跡します; con.cursor().execute("SELECT current_schema()").fetchone() が引き続き main ではなく other_schema を返せば完了です。

索引モデルが issue の本文から書いたものです。