Fix extra facets

[bouweandela]

Description

Closes #1355

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[codecov]

Codecov Report

Merging #1360 (3e53b5b) into main (3c3f5cb) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1360   +/-   ##
=======================================
  Coverage   88.26%   88.26%           
=======================================
  Files         194      194           
  Lines        9836     9836           
=======================================
  Hits         8682     8682           
  Misses       1154     1154           

Impacted Files	Coverage Δ
esmvalcore/_config/_config.py	95.48% <100.00%> (ø)

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