Add FortiOS test

[JSCU-CNI]

This PR adds a FortiOS test to dissect.

[codecov]

Codecov Report

Attention: Patch coverage is 42.85714% with 4 lines in your changes missing coverage. Please review.

Project coverage is 77.50%. Comparing base (ff97254) to head (7cf60b4).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...issect/target/plugins/os/unix/linux/fortios/_os.py	42.85%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #945      +/-   ##
==========================================
+ Coverage   77.06%   77.50%   +0.44%     
==========================================
  Files         323      323              
  Lines       27641    27647       +6     
==========================================
+ Hits        21301    21429     +128     
+ Misses       6340     6218     -122     

Flag	Coverage Δ
unittests	77.50% <42.85%> (+0.44%)	⬆️

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