[TEST] Sort_utils

[OmaymaMahjoub]

What do you want to test?

Sorting utils (in mava/utils/sort_utils).

Outline of test structure

• Unit tests

Definition of done

Passing checks, cover edge cases.

Mandatory checklist before making a PR

• [ ] The success criteria laid down in “Definition of done” are met.
• [ ] Test code is documented - docstrings for methods and classes, static types for arguments.
• [ ] Documentation is updated - README, CONTRIBUTING, or other documentation.

PS. The test should be in a new sensible folder when you make it, e.g. tests/utils