GetGDCMSeriesFileNames() returns list not in order when feed with data containing duplicate slices #2176

Describe the bug

series_reader = sitk.ImageSeriesReader()
series_ids = series_reader.GetGDCMSeriesIDs(source)
series_files = {series_id: series_reader.GetGDCMSeriesFileNames(source, series_id)
                    for series_id in series_ids}

When source contains duplicate slices. The returned series_files is not in order. And no error or warning is thrown.

To Reproduce
Steps to reproduce the behavior:

1. Operating system, version, and architecture

• OS: Ubuntu 24.04 LTS
• Architecture: 12th Gen Intel® Core™ i7-1265U × 12

2. Programming language, and version
   Python 3.8.19
3. Version of SimpleITK
   2.2.1
4. How was SimpleITK installed?

• binary distribution [e.g. python -m pip install SimpleITK]