Clean Modelator data directory after update

[rnbguy]

Closes: #147

Description

Removes unexpected jars from Modelator data directory.

This usually happens when we update a model checker jar with a latest one.

_{This feature would be deprecated soon and use release assets from original releases.}

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For contributor use:

• If applicable, unit tests are written and added to CI. Already taken care of.
• Ran go fmt, cargo fmt and etc. (or had formatting run automatically on all files edited)
• Updated relevant documentation (docs/) and code comments. Not needed.
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Re-reviewed Files changed in the Github PR explorer.
• Added a changelog entry, using unclog.