Fix a bug when computing the transfer matrix with remeshing

[sblauth]

This PR merges a fix for computing the transfer matrix. This was not done correctly when the geometry was remeshed multiple times.

[codecov]

Codecov Report

Merging #244 (ea9e14e) into main (ce07e8e) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #244   +/-   ##
=======================================
  Coverage   92.62%   92.63%           
=======================================
  Files          83       83           
  Lines        6426     6430    +4     
=======================================
+ Hits         5952     5956    +4     
  Misses        474      474           

Impacted Files	Coverage Δ
cashocs/_database/database.py	100.00% <100.00%> (ø)
cashocs/_database/geometry_database.py	100.00% <100.00%> (ø)
cashocs/_optimization/line_search/line_search.py	100.00% <100.00%> (ø)
cashocs/geometry/mesh_handler.py	93.73% <100.00%> (ø)

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