build: drop support for Python 3.9

[RobPasMue]

Description

Dropping support for Python 3.9 following SPEC-0 and ADR 21 (Ansys internal)

Issue linked

None

Checklist

• I have tested my changes locally.
• I have added necessary documentation or updated existing documentation.
• I have followed the coding style guidelines of this project.
• I have added appropriate unit tests.
• 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 added the minimum version decorator to any new backend method implemented.
• I have made sure that the title of my PR follows Conventional commits style (e.g. feat: extrude circle to cylinder)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.93%. Comparing base (d942b59) to head (cd712b8).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1341   +/-   ##
=======================================
  Coverage   91.93%   91.93%           
=======================================
  Files          86       86           
  Lines        6754     6754           
=======================================
  Hits         6209     6209           
  Misses        545      545           

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