vortex_arrays::assertions::assert_arrays_eq forces users to install itertools

[harryscholes]

Issue Description

assert_arrays_eq! forces users to install itertools inside the calling crate. The itertools dependency inside vortex-arrays does not get used because the macro splices the macro body into the calling code. Adding itertools to the calling crate's Cargo.toml works.

Expected Behavior

assert_arrays_eq! should just work.

Actual Behavior

error[E0433]: failed to resolve: use of unresolved module or unlinked crate `itertools`
  --> src/main.rs:58:5
   |
58 |     assert_arrays_eq!(&a, &a);
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ use of unresolved module or unlinked crate `itertools`
   |
   = help: if you wanted to use a crate named `itertools`, use `cargo add itertools` to add it to your `Cargo.toml`
   = note: this error originates in the macro `assert_arrays_eq` (in Nightly builds, run with -Z macro-backtrace for more info)

Reproduction Steps

use vortex::{arrays::PrimitiveArray, buffer::buffer, validity::Validity};
use vortex_array::assert_arrays_eq;

fn main() {
    let a = PrimitiveArray::new(buffer![1u64, 2, 3], Validity::NonNullable);
    assert_arrays_eq!(&a, &a);
}

OS Version Information

macOS 15.6.1

I acknowledge that:

• I have searched the Vortex repository (both open and closed Discussions and Issues) and confirm this is not a duplicate of an existing issue or discussion.
• I have checked the "Preview" tab on all text fields to ensure that everything looks right, and have wrapped all configuration and code in code blocks with a group of three backticks (```) on separate lines.

[robert3005]

This has been fixed in #5543