fix: pyvista version

[germa89]

Description

Fix pyvista dependency while we figure out what to do with #4157

Issue linked

Related #4157

Checklist

• I have visited and read Develop PyMAPDL.
• I have tested my changes locally
• I have added necessary documentation or updated existing documentation.
• I have followed the PyMAPDL coding style guidelines.
• I have added appropriate unit tests that also ensure the minimal coverage criteria.
• I have reviewed my changes before submitting this pull request.
• I have linked the issue or issues that are solved to the PR if any.
• I have assigned this PR to myself.
• I have marked this PR as draft if it is not ready to be reviewed yet.
• I have made sure that the title of my PR follows Commit naming conventions (e.g. feat: adding new MAPDL command)

[Copilot]

Pull Request Overview

This PR fixes the pyvista dependency version to resolve compatibility issues. The change constrains pyvista to version 0.45.2 or lower while a longer-term solution is developed for issue #4157.

• Adds version constraint to pyvista dependency

[germa89]

@pyansys-ci-bot LGTM.

[pyansys-ci-bot]

✅ Approving this PR because germa89 said so in here 😬

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.33%. Comparing base (514cfae) to head (04f9cb6).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4158      +/-   ##
==========================================
+ Coverage   91.30%   91.33%   +0.03%     
==========================================
  Files         189      193       +4     
  Lines       15698    15722      +24     
==========================================
+ Hits        14333    14360      +27     
+ Misses       1365     1362       -3     

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