Set zip(..., strict=True) in key solver/expression tree files for len…

[swastim01]

Set zip(..., strict=True) in key solver/expression tree files for length safety

Description

This PR updates the solver and expression tree files to use zip(..., strict=True) where appropriate. This ensures that all zip operations fail fast if input iterables have mismatched lengths, improving code safety and preventing subtle bugs.

Fixes #5060

Type of change

• Bug fix (non-breaking change which improves code safety)

Changelog

Please add a line in the relevant section of CHANGELOG.md to document the change (include PR #):

## Bug Fixes

- Set `zip(..., strict=True)` in solver and expression tree files to ensure iterable length safety. ([#5241](https://github.com/pybamm-team/PyBaMM/pull/5241))

Important checks

Please confirm the following before marking the PR as ready for review:

• No style issues: nox -s pre-commit
• All tests pass: nox -s tests
• Documentation builds: nox -s doctests
• Code is commented for hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.82%. Comparing base (d536255) to head (78f3ec4).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #5241   +/-   ##
========================================
  Coverage    98.82%   98.82%           
========================================
  Files          321      321           
  Lines        27491    27491           
========================================
  Hits         27169    27169           
  Misses         322      322           

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[MarcBerliner]

Thanks @swastim01, just one thing to clean up the changelog. Otherwise, looks good to me!

[MarcBerliner]

Thanks!