Fix locate entities

[RemDelaporteMathurin]

Proposed changes

Fix for #908 + other bug found in the creation of D_global

Types of changes

What types of changes does your code introduce to FESTIM?

• [x] Bugfix (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
• [ ] Documentation Update (if none of the other choices apply)
• [ ] New tests

Checklist

• [x] Black formatted
• [x] Unit tests pass locally with my changes
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have added necessary documentation (if appropriate)

[codecov[bot]]

Codecov Report

:x: Patch coverage is 90.00000% with 6 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 95.78%. Comparing base (5413431) to head (2387a82). :warning: Report is 146 commits behind head on fenicsx.

Files with missing lines	Patch %	Lines
src/festim/mesh/mesh.py	87.50%	2 Missing :warning:
src/festim/exports/maximum_surface.py	88.88%	1 Missing :warning:
src/festim/exports/maximum_volume.py	90.00%	1 Missing :warning:
src/festim/exports/minimum_surface.py	88.88%	1 Missing :warning:
src/festim/exports/minimum_volume.py	90.00%	1 Missing :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##           fenicsx     #981      +/-   ##
===========================================
- Coverage    95.88%   95.78%   -0.10%     
===========================================
  Files           46       46              
  Lines         2721     2802      +81     
===========================================
+ Hits          2609     2684      +75     
- Misses         112      118       +6     

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[RemDelaporteMathurin]

Could maybe add some tests for the multispecies cases?

I did: https://github.com/festim-dev/FESTIM/blob/2387a82ac7ad56b2c83a4df5f3ef1c6eed6daebd/test/system_tests/test_misc.py#L91-L98