Qol auto detect surface to volume

[RemDelaporteMathurin]

Description

Needs #1118

Summary

This PR removes the need to explicitly define surface_to_volume when initiliasing a HydrogenTransportProblemDiscontinuous class

Related Issues

Fixes #1117

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 🔨 Code refactoring (no functional changes, no API changes)
• 📝 Documentation update
• ✅ Test update (adding missing tests or correcting existing tests)
• 🔧 Build/CI configuration change

Testing

• All existing tests pass locally (pytest)
• I have added new tests that prove my fix is effective or that my feature works

Code Quality Checklist

• My code follows the code style of this project (Ruff formatted: ruff format .)
• My code passes linting checks (ruff check .)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas

Documentation

• I have updated the documentation accordingly (if applicable)
• I have added docstrings to new functions/classes following the project conventions

Breaking Changes

Screenshots/Examples

Additional Notes

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.80%. Comparing base (33ea49e) to head (fd21218).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/festim/subdomain/volume_subdomain.py	86.11%	5 Missing ⚠️
src/festim/hydrogen_transport_problem.py	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1122      +/-   ##
==========================================
- Coverage   94.92%   94.80%   -0.12%     
==========================================
  Files          44       44              
  Lines        3270     3310      +40     
==========================================
+ Hits         3104     3138      +34     
- Misses        166      172       +6     

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[jhdark]

This is a great little quality of life change! Just made some small suggestions to allow things to still work in parallel.

[jhdark]

Should we add some kind of "deprecation" warning only for the next release, just noting that this is no longer required to be given by the user if a non-empty dict is given? Even though its not a deprecation

[RemDelaporteMathurin]

yes there is a a DeprecationWarning in HydrogenTransportProblemDiscontinuous.initialise()

https://github.com/festim-dev/FESTIM/pull/1122/changes#diff-586fa3ee395f75eb89f7d327f2f051a08b9d4f0cb520918f7e112d3ac7271af8R1142-R1150