xgboost: add clipping of loss values to the float32 limits

[AldoGl]

Proposed changes

Internally the XGBoost routine operates a conversion to float32, and this fails if the absolute values of the loss are exceedingly large. This commit adds a simple clipping operation before the loss values are passed to the XGBoost package.

Types of changes

What types of changes does your code introduce?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

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• I have read the CONTRIBUTING doc
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works

[codecov-commenter]

Codecov Report

Merging #35 (37ab3e7) into main (03da1df) will decrease coverage by 0.03%.
The diff coverage is 94.11%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #35      +/-   ##
==========================================
- Coverage   97.21%   97.17%   -0.04%     
==========================================
  Files          29       29              
  Lines        1435     1452      +17     
==========================================
+ Hits         1395     1411      +16     
- Misses         40       41       +1     

Impacted Files	Coverage Δ
black_it/samplers/xgboost.py	98.21% <94.11%> (-1.79%)	⬇️

[muxator]

• split the PR in two commits. The first one triggers the problem, the second one shows the fix. The final version is the same as the one submitted by @AldoGl.
• some lint fixes

[AldoGl]

• split the PR in two commits. The first one triggers the problem, the second one shows the fix. The final version is the same as the one submitted by @AldoGl.
• some lint fixes

Thank you for your help @muxator, merging now!