Remove SOFC Keras Surrogates And Tests

[bpaul4]

Fixes

Closes #1431

Summary/Motivation:

Remove SOFC Keras surrogates that no longer work, as they as no longer used anywhere in the codebase.

Legal Acknowledgement

By contributing to this software project, I agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the license terms described in the LICENSE.txt file at the top level of this directory.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.36%. Comparing base (ff6471c) to head (8f724fb).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1475   +/-   ##
=======================================
  Coverage   76.36%   76.36%           
=======================================
  Files         394      393    -1     
  Lines       65136    65085   -51     
  Branches    14429    14426    -3     
=======================================
- Hits        49743    49705   -38     
+ Misses      12831    12819   -12     
+ Partials     2562     2561    -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[AlexNoring]

lgtm

[lbianchi-lbl]

Thanks a lot @bpaul4. We're trying to get #1465 merged ASAP, and then we'll merge this in whenever possible after that.