save step and cycle number from a solution

[valentinsulzer]

Description

I keep doing this manually and it might be useful here instead

Type of change

Please add a line in the relevant section of CHANGELOG.md to document the change (include PR #) - note reverse order of PR #s. If necessary, also add to the list of breaking changes.

• New feature (non-breaking change which adds functionality)
• Optimization (back-end change that speeds up the code)
• Bug fix (non-breaking change which fixes an issue)

Key checklist:

• No style issues: $ pre-commit run (see CONTRIBUTING.md for how to set this up to run automatically when committing locally, in just two lines of code)
• All tests pass: $ python run-tests.py --all
• The documentation builds: $ python run-tests.py --doctest

You can run unit and doctests together at once, using $ python run-tests.py --quick.

Further checks:

• Code is commented, particularly in hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.02 🎉

Comparison is base (1928b19) 99.68% compared to head (8dda652) 99.71%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2931      +/-   ##
===========================================
+ Coverage    99.68%   99.71%   +0.02%     
===========================================
  Files          273      273              
  Lines        18997    19002       +5     
===========================================
+ Hits         18938    18947       +9     
+ Misses          59       55       -4     

Impacted Files	Coverage Δ
...bamm/expression_tree/operations/evaluate_python.py	99.29% <ø> (ø)
pybamm/solvers/jax_bdf_solver.py	98.89% <100.00%> (+0.85%)	⬆️
pybamm/solvers/solution.py	100.00% <100.00%> (ø)
pybamm/util.py	100.00% <100.00%> (ø)

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[brosaplanella]

Looks good, thanks!