Improvement: Vtk-writer

[Davknapp]

Closes #1937

Some of the function in the vtk-writer had misleading and unnecessary fields in the interface. This PR fixes it.

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.63%. Comparing base (d360380) to head (b7a7cec).
⚠️ Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
src/t8_vtk/t8_vtk_writer_helper.cxx	0.00%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1936      +/-   ##
==========================================
- Coverage   75.77%   75.63%   -0.15%     
==========================================
  Files         103      103              
  Lines       19230    18625     -605     
==========================================
- Hits        14572    14087     -485     
+ Misses       4658     4538     -120     

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.46%. Comparing base (e5ab1b8) to head (535e7c1).
⚠️ Report is 62 commits behind head on main.

Files with missing lines	Patch %	Lines
src/t8_vtk/t8_vtk_writer_helper.cxx	0.00%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1936      +/-   ##
==========================================
- Coverage   77.47%   77.46%   -0.01%     
==========================================
  Files         112      112              
  Lines       19088    19090       +2     
==========================================
  Hits        14788    14788              
- Misses       4300     4302       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[sandro-elsweijer]

Ahhh merge conflicts @Davknapp