Move two test files that don't need to be isolated

[tleonhardt]

Move two test files that don't need to be isolated from tests_isolated directory to tests directory.

Also:

• Remove unnecessary nested directory under tests_isolated for the one remaining test file there.

This is the first step in fixing the tests so none of them need to be isolated. The tests in tests_isolated/test_commandset.py follow bad practices where classes are modified instead of instances of classes.

[github-actions]

🤖 Hi @tleonhardt, I've received your request, and I'm working on it now! You can track my progress in the logs for more details.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.90%. Comparing base (bad67dc) to head (3194dbe).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1519      +/-   ##
==========================================
- Coverage   98.92%   98.90%   -0.03%     
==========================================
  Files          21       21              
  Lines        4933     4933              
==========================================
- Hits         4880     4879       -1     
- Misses         53       54       +1     

Flag	Coverage Δ
unittests	98.90% <ø> (-0.03%)	⬇️

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[github-actions]

📋 Review Summary

This pull request refactors the test suite by moving tests from the tests_isolated directory to the tests directory and adding a new ExternalTestMixin to tests/conftest.py to help with testing. The changes are well-structured and improve the organization of the tests.

🔍 General Feedback

• The new ExternalTestMixin is a great addition for testing cmd2 applications.
• The docstrings in the new mixin could be more descriptive to improve clarity and maintainability.