Fix ragged nested sequence warning

[Foxglove144]

Description

Addressed the VisibleDeprecationWarning related to creating an ndarray from ragged nested sequences in the script. Modified the analyze_by_distance function and analyze_by_size function to specify dtype=object when creating the np.asarray() array containing all_assigned_clean. This ensures that the array can handle objects of different types or shapes without triggering the deprecation warning

Fixes # (issue)

Type of change

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• Improvement (non-breaking)
• Bug fix (non-breaking)
• New feature (non-breaking)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Testing

Please describe the tests that you ran to verify your changes. Consider listing any relevant details of your test configuration.

• Test A
• Test B

Test Configuration:

• OS
• Python version
• ART version or commit number
• TensorFlow / Keras / PyTorch / MXNet version

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[codecov-commenter]

Codecov Report

Merging #2195 (6250986) into dev_1.15.0 (82f8fa2) will decrease coverage by 0.31%.
The diff coverage is 100.00%.

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@@              Coverage Diff               @@
##           dev_1.15.0    #2195      +/-   ##
==============================================
- Coverage       85.61%   85.30%   -0.31%     
==============================================
  Files             308      308              
  Lines           27448    27448              
  Branches         5044     5044              
==============================================
- Hits            23499    23415      -84     
- Misses           2669     2755      +86     
+ Partials         1280     1278       -2     

Impacted Files	Coverage Δ
...rt/defences/detector/poison/clustering_analyzer.py	94.93% <100.00%> (ø)

... and 4 files with indirect coverage changes

[beat-buesser]

Hi @Foxglove144 Thank you very much for fixing this deprecation warning!