Ensure cond field in heat equation is reshaped in f-order

[larsevj]

Before change:

After change:

• PR title captures the intent of the changes, and is fitting for release notes.
• Added appropriate release note label
• Commit history is consistent and clean, in line with the contribution guidelines.
• Make sure unit tests pass locally after every commit (git rebase -i main --exec 'just rapid-tests')

When applicable

• When there are user facing changes: Updated documentation
• New behavior or changes to existing untested code: Ensured that unit tests are added (See Ground Rules).
• Large PR: Prepare changes in small commits for more convenient review
• Bug fix: Add regression test for the bug
• Bug fix: Add backport label to latest release (format: 'backport release-branch-name')

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.02%. Comparing base (d6b790b) to head (b009470).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #13384      +/-   ##
==========================================
+ Coverage   90.00%   90.02%   +0.02%     
==========================================
  Files         457      457              
  Lines       31803    31803              
==========================================
+ Hits        28623    28632       +9     
+ Misses       3180     3171       -9     

Flag	Coverage Δ
cli-tests	37.42% <ø> (ø)
fuzz	44.27% <ø> (ø)
gui-tests	67.04% <ø> (ø)
performance-and-unit-tests	77.99% <ø> (+0.09%)	⬆️
test	45.94% <ø> (ø)

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see 3 files with indirect coverage changes

[dafeda]

Nice catch! This does look better.

[codspeed-hq]

Merging this PR will not alter performance

✅ 36 untouched benchmarks

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_{Comparing larsevj:ensure_cond_field_reshaped_in_fortran_order (b009470) with main (d6b790b)}