Correct temperature and salinity mean diagnostics when using conservative/absolute

[breichl]

This addresses issue #858.

• Previously the global/area mean temperature and salinity outputs were the model prognostic temp/salt, but were always reported as potential temperature and practical salinity.
• This gives the correction for those outputs so it is actually potential temperature and practical salinity, even when the model is conservative and absolute.
• The option is also added to output the averaged conservative temperature and absolute salinity variables when those are the prognostic variables.
• The option to output conservative temp and absolute salinity when model is potential temp and practical salinity is not added.
• This PR will change the horizontally averaged T&S output data for cases that used conservative temp and absolute salinity by applying the correction before the averaging.

[breichl]

I believe the checks that failed are expected. My inclination is to not wrap "bugfix" changes around these unless necessary since it is only diagnostics that change. But I'm unsure if it will impact other users, I'm not sure if anyone else has started using the TEOS-10 EOS.

[marshallward]

It looks to me like they are identical but in a different order?

[breichl]

It looks to me like they are identical but in a different order?

Oh good point, yes in these runs they should be identical. They will only change for cases that used the conservative temp/absolute salinity.

[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 36 lines in your changes missing coverage. Please review.

Project coverage is 38.06%. Comparing base (c73ad58) to head (a11329d).

Files with missing lines	Patch %	Lines
src/diagnostics/MOM_diagnostics.F90	40.00%	36 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           dev/gfdl     #860      +/-   ##
============================================
- Coverage     38.07%   38.06%   -0.01%     
============================================
  Files           298      298              
  Lines         87946    87988      +42     
  Branches      16508    16520      +12     
============================================
+ Hits          33482    33490       +8     
- Misses        48411    48446      +35     
+ Partials       6053     6052       -1     

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

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[marshallward]

We decided to let this in for now and then (hopefully) try to update the testing to handle this before it gets shipped to mom-ocean.

[marshallward]

Gaea regression: https://gitlab.gfdl.noaa.gov/ogrp/mom6ci/MOM6/-/jobs/151913 ✔️ 🟡

New diagnostics added to available_diags.*.