For R.C. - Fleet UI: Linux only .sh software installer

[RachelElysia]

Issue

The first issue of #34953

Description

@sgress454 and I on each others toes with this due to both of us working on .sh but for scripts its for macOS and Linux but for software installers its only available for Linux.

• The permanent fix is already in main in this large PR pushed to 4.77 Fleet UI: IPA custom packages #34220 so I had to cherry pick these file fixes specifically

Screenshots of fixes

• QA'd all new/changed functionality manually

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (rc-minor-fleet-v4.76.0@2602652). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
frontend/utilities/file/fileUtils.tsx	83.33%	1 Missing ⚠️

Additional details and impacted files

@@                    Coverage Diff                    @@
##             rc-minor-fleet-v4.76.0   #35013   +/-   ##
=========================================================
  Coverage                          ?   64.25%           
=========================================================
  Files                             ?     2062           
  Lines                             ?   207750           
  Branches                          ?     7091           
=========================================================
  Hits                              ?   133494           
  Misses                            ?    63791           
  Partials                          ?    10465           

Flag	Coverage Δ
frontend	53.77% <83.33%> (?)

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