Fix WCRP Geophysical Variable Detection for hybrid-height variables (cl/cli/clw)

[rhaegar325]

Summary

After CMORisation renames the hybrid-height coordinate variables, the
coordinates and formula_terms attribute strings still referenced the
pre-rename input names. Those names no longer exist in the output, so the WCRP
wcrp_cmip6:1.0 Geophysical Variable Detection check mis-classified the
formula-term variables (b, orog) as data variables.

Problem

Dataset.rename() relabels variables but not the attribute strings that
reference them. For cl (and cli/clw):

cl:  coordinates  = "sigma_theta surface_altitude theta_level_height"  # none exist
lev: formula_terms = "a: theta_level_height b: sigma_theta orog: surface_altitude"

The real variables are b, orog, lev. Because the checker only excludes a
variable when it is referenced by a coordinates attribute (it ignores
formula_terms), b and orog were counted as geophysical:

Expected exactly 1 geophysical variable, found 3: ['b', 'cl', 'orog']

Fix

New helper Atmosphere_CMORiser._retarget_renamed_references(rename_map), called
right after self.ds.rename(rename_map), rewrites every coordinates /
formula_terms string to the post-rename names. Only tokens that are keys in
the rename map are changed, so non-hybrid variables are untouched.

The full intended rename {**bounds_rename_map, **axes_rename_map} is passed
(not the filtered map used by rename()): the cl_level_to_height
dataset_function renames theta_level_height -> lev itself, so that key is
absent from the filtered map yet still appears in the attribute strings.

cl:  coordinates  = "b orog lev"
lev: formula_terms = "a: lev b: b orog: orog"

(There is no missing a variable: the a term is the level-height coordinate,
i.e. lev.)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.0%. Comparing base (85df727) to head (af2754f).

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #403     +/-   ##
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+ Coverage   74.9%   75.0%   +0.1%     
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  Files         28      28             
  Lines       5246    5258     +12     
  Branches     963     967      +4     
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+ Hits        3929    3941     +12     
  Misses      1092    1092             
  Partials     225     225             

Flag	Coverage Δ
unit	75.0% <100.0%> (+0.1%)	⬆️

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