Fix bug when using ipy with gnureadline and Python 3.13

[tleonhardt]

Fixes #1357

This PR is a workaround to fix a bizarre bug that happens when the ipy command is executed when using gnureadline with Python 3.13 on Mac or Linux.

We aren't sure if the fundamental underlying bug exists within gnureadline, ipython, or readline; but this workaround does appear to be a solid method for preventing it.

NOTE: This PR is slightly more complicated than need be. Strictly only the try/import at the beginning is necessary. The other code within ipy where we import start_ipython from IPython if it doesn't already exist is to support the rare case that developers have actually used many times in the real world where ipython isn't installed at first and you encounter a bug in a cmd2 application and then install ipython from within the cmd2 app and then execute ipy to help debug the problem.

Also:

• Added invoke tasks for cleaning up the ruff cache directory

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.58%. Comparing base (ff46021) to head (4dca320).
Report is 27 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1358      +/-   ##
==========================================
+ Coverage   97.72%   98.58%   +0.86%     
==========================================
  Files          22       22              
  Lines        5753     5796      +43     
==========================================
+ Hits         5622     5714      +92     
+ Misses        131       82      -49     

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