`ScalarValue::iter_to_array` accepts mismatched type parameters

[Theodus]

Describe the bug

ScalarValue::iter_to_array accepts scalars with the same enum variant but different DataType parameters. It builds the output array with the first scalar's parameters and discards the later parameters.

This affects:

• Decimal32, Decimal64, Decimal128, and Decimal256 precision and scale
• Timestamp timezones for every time unit
• FixedSizeBinary widths

To Reproduce

use datafusion_common::ScalarValue;

let scalars = [
    ScalarValue::Decimal128(Some(100), 10, 2),
    ScalarValue::Decimal128(Some(100), 11, 2),
];

// This succeeds and uses precision 10 instead of returning an error.
assert!(ScalarValue::iter_to_array(scalars).is_ok());

Expected behavior

ScalarValue::iter_to_array should return an error when decimal precision, decimal scale, timestamp timezone, or fixed-size binary width differs.

Additional context

No response

[Theodus]

take