test(rust): Add test for CSV parsing of quoted fields with line breaks

[demetribu]

Add test for CSV parsing of quoted fields with line breaks

• Implements a new test case test_quoted_fields_with_line_breaks in the CSV module.
• This test verifies that Polars correctly handles quoted fields containing line breaks within CSV files.
• Ensures that multiline strings within quotes are read as a single field without errors.

[ritchie46]

Is there any reason you write this test? I am fairly positive we already test this.

[alexander-beedie]

Yup; test_skip_new_line_embedded_lines covers newlines in CSV string values.