Add test coverage for bin_image_series optional parameters

[coderabbitai]

Description

Add test coverage for the mdx2.bin_image_series command to verify correct behavior with various combinations of optional parameters.

Test Scenarios Needed

The following combinations should be tested:

1. With mask, with valid_range: Verify binning respects both mask and valid data range
2. With mask, without valid_range: Verify binning applies mask only
3. Without mask, with valid_range: Verify binning applies valid range filtering only
4. Without mask, without valid_range: Verify basic binning without filtering

Additional Considerations

• Verify that optional parameters are truly optional (no defaults cause required arg behavior)
• Test that mask files are loaded correctly when provided
• Test that valid_range tuples are parsed and applied correctly
• Verify output correctness for each scenario

Context

Related to PR #45 and discussion at:

• PR: Spm/44 prepare new release #45
• Discussion: Spm/44 prepare new release #45 (comment)

Requested by: @spmeisburger