Added test to capture edge cases with unsorted count

[ezrasingh]

Description

This PR introduces a new test to handle edge cases when querying for nearest_n_within. The test is designed to ensure that the nearest_n_within function behaves as expected, particularly with the max_qty and sorted parameters.

Key Changes:

• Added a new test function can_query_nearest_n_items_unsorted_max_qty in src/float/query/nearest_n_within.rs.
• The test covers scenarios with both non-zero and zero values for max_qty, verifying that the function returns the correct number of results when sorted or unsorted.

Confirmation of Fix:

This test confirms that the fix introduced in PR #175 for issue #168 works as intended.

However, it also reveals that the function behaves differently when max_qty is set to 0, depending on whether the results are sorted or not. When sorted is true, the function handles max_qty = 0 correctly, but when sorted is false, it fails to return the expected empty result set.

This addition helps to ensure that edge cases are handled correctly and that the nearest_n_within function performs consistently under various conditions.

[sdd]

Thanks for another great contribution - approved! I'll make sure I get the unreleased changes out today, sorry for the delay.