3958 hcd efficiencies missing as inputs

[j-a-foster]

Description

This adds the wall plug efficiencies for the EBW and ICRH HCD models as inputs and changed their default values to avoid a divide by zero error when running them.

A bug was also found in the EBW efficiency model where the wrong units were used for electron density. This resulted in the efficiency always being zero. This has been corrected and tests have been added for the HCD efficiency models that weren't tested.

Checklist

I confirm that I have completed the following checks:

• My changes follow the PROCESS style guide
• I have justified any large differences in the regression tests caused by this pull request in the comments.
• I have added new tests where appropriate for the changes I have made.
• If I have had to change any existing unit or integration tests, I have justified this change in the pull request comments.
• If I have made documentation changes, I have checked they render correctly.
• I have added documentation for my change, if appropriate.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.24%. Comparing base (633a49e) to head (44173d2).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3961      +/-   ##
==========================================
+ Coverage   45.98%   46.24%   +0.25%     
==========================================
  Files         123      123              
  Lines       28550    28550              
==========================================
+ Hits        13129    13203      +74     
+ Misses      15421    15347      -74     

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