Fix up some things that have changed with Prusa Slicer

[iterion]

Just found these small issues when running again locally today. One is just a change related to where Prusa installs on macos. The other is to just always assume Usb printers are idle until we can better handle print state.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 24.14%. Comparing base (4fce706) to head (c5ad358).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/usb/control.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #248   +/-   ##
=======================================
  Coverage   24.14%   24.14%           
=======================================
  Files          46       46           
  Lines        3164     3164           
=======================================
  Hits          764      764           
  Misses       2400     2400           

Flag	Coverage Δ
unittests	24.14% <0.00%> (ø)

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