fix: hotfix scale decoder norm is not passed to training sae

[chanind]

Description

In #365, we fixed a bug where the scale_sparsity_penalty_by_decoder_norm was being ignored and the SAE was always scaling by decoder norm regardless. However, this fix revealed a second bug where we're not passing the scale_sparsity_penalty_by_decoder_norm param through to the training SAE at all. This sort of bug is easy to happen given that we create the TrainingSAEConfig from the runner config via creating a dictionary without type checking.

This PR adds a test just that scale_sparsity_penalty_by_decoder_norm is now being passed through correctly to get this fix out asap, but I'll make a follow-up PR with a more robust fix in the form of better tests or type checking or something after this is merged.

Type of change

Please delete options that are not relevant.

• Bug fix (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)
• This change requires a documentation update

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• 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
• I have not rewritten tests relating to key interfaces which would affect backward compatibility

You have tested formatting, typing and unit tests (acceptance tests not currently in use)

• I have run make check-ci to check format and linting. (you can run make format to format code if needed.)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.74%. Comparing base (17506ac) to head (4f28b21).
Report is 2 commits behind head on main.

Additional details and impacted files

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  Coverage   72.74%   72.74%           
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  Files          22       22           
  Lines        3266     3266           
  Branches      431      431           
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  Hits         2376     2376           
  Misses        762      762           
  Partials      128      128           

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