[sc-69429] SPSA keyword argument bug fix

[isaacdevlugt]

Context: SPSAOptimizer's step_and_cost method was ignoring keyword arguments in the objective function.

Description of the Change: SPSAOptimizer.step_and_cost no longer ignores kwargs.

Benefits: Your keyword arguments are heard <3

Possible Drawbacks: None

Related github issue: #6028

[Shiro-Raven]

Is there a reason why no tests are added to address this fix? Was a test failing before? Or an issue that brought attention to this bug?

[dwierichs]

Thanks for the quick fix, @isaacdevlugt ! 🎉
I am wondering whether the function evaluation that needed fixing actually is required, or whether we can get the output shape from the evaluations we are doing anyways? And it might be nice to have a test that catches this bug, i.e. fails on current master.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.65%. Comparing base (3ad15d7) to head (9c1bedb).
Report is 4 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6027      +/-   ##
==========================================
- Coverage   99.66%   99.65%   -0.01%     
==========================================
  Files         427      427              
  Lines       41057    40764     -293     
==========================================
- Hits        40919    40624     -295     
- Misses        138      140       +2     

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[dwierichs]

Could continue discussing the necessity for the extra evaluation for extracting the shape, but as this is not the purpose of the PR, also good to merge without addressing it for now.
Thanks!

[KetpuntoG]

Looks great! Thanks for working on this