[MAINT] Refactor fixture for plotting

[Remi-Gau]

• Closes rename / refactor plotting specific fixture in conftest.py #3725

Changes proposed in this pull request:

• extract several fixtures from a single complex one used for plotting

[github-actions]

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[codecov]

Codecov Report

Merging #4057 (abb0185) into main (7739f95) will decrease coverage by 0.27%.
Report is 17 commits behind head on main.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #4057      +/-   ##
==========================================
- Coverage   91.75%   91.48%   -0.27%     
==========================================
  Files         145      143       -2     
  Lines       16222    16076     -146     
  Branches     3370     3340      -30     
==========================================
- Hits        14884    14707     -177     
- Misses        795      823      +28     
- Partials      543      546       +3     

Flag	Coverage Δ
macos-latest_3.10	?
macos-latest_3.11	91.47% <ø> (-0.21%)	⬇️
macos-latest_3.12	91.47% <ø> (-0.21%)	⬇️
macos-latest_3.8	91.43% <ø> (-0.21%)	⬇️
macos-latest_3.9	91.43% <ø> (-0.21%)	⬇️
ubuntu-latest_3.10	91.47% <ø> (?)
ubuntu-latest_3.11	91.47% <ø> (?)
ubuntu-latest_3.12	91.47% <ø> (-0.21%)	⬇️
ubuntu-latest_3.8	91.43% <ø> (-0.21%)	⬇️
ubuntu-latest_3.9	91.43% <ø> (-0.21%)	⬇️
windows-latest_3.10	91.41% <ø> (-0.21%)	⬇️
windows-latest_3.11	91.41% <ø> (-0.21%)	⬇️
windows-latest_3.12	?
windows-latest_3.8	91.37% <ø> (-0.21%)	⬇️
windows-latest_3.9	91.38% <ø> (-0.21%)	⬇️

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[bthirion]

LGTM, thx.