[RTR] Names of variables in figures handles variable mapping

[Ipuch]

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related to #523

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This change is 

[codecov]

Codecov Report

Base: 80.49% // Head: 83.86% // Increases project coverage by +3.37% 🎉

Coverage data is based on head (8ff7528) compared to base (e831e3a).
Patch coverage: 86.80% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #524      +/-   ##
==========================================
+ Coverage   80.49%   83.86%   +3.37%     
==========================================
  Files          87       88       +1     
  Lines        9552     9690     +138     
==========================================
+ Hits         7689     8127     +438     
+ Misses       1863     1563     -300     

Impacted Files	Coverage Δ
bioptim/optimization/solution.py	85.56% <ø> (ø)
bioptim/gui/graph.py	95.20% <50.00%> (-0.27%)	⬇️
bioptim/dynamics/integrator.py	94.73% <69.23%> (-2.20%)	⬇️
...mples/getting_started/example_implicit_dynamics.py	89.47% <77.27%> (+44.54%)	⬆️
bioptim/dynamics/configure_problem.py	90.07% <77.94%> (-1.58%)	⬇️
bioptim/dynamics/dynamics_functions.py	96.32% <87.50%> (-1.85%)	⬇️
bioptim/limits/constraints.py	83.63% <97.50%> (+6.55%)	⬆️
bioptim/__init__.py	100.00% <100.00%> (ø)
bioptim/dynamics/dynamics_evaluation.py	100.00% <100.00%> (ø)
bioptim/dynamics/ode_solver.py	88.69% <100.00%> (+0.30%)	⬆️
... and 16 more

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[pariterre]

Reviewed 3 of 3 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @Ipuch)

[pariterre]

Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @Ipuch)