Add instructions for command line installation on pkg gen

[dantecatalfamo]

#25004

• Changes file added for user-visible changes in changes/, orbit/changes/ or ee/fleetd-chrome/changes.
  See Changes files for more information.
• Manual QA for all new/changed functionality

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 63.83%. Comparing base (efe3315) to head (3a42af9).
Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/fleetctl/package.go	50.00%	9 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main   #25166    +/-   ##
========================================
  Coverage   63.83%   63.83%            
========================================
  Files        1615     1615            
  Lines      153602   153712   +110     
  Branches     3986     3986            
========================================
+ Hits        98046    98128    +82     
- Misses      47754    47775    +21     
- Partials     7802     7809     +7     

Flag	Coverage Δ
backend	64.71% <50.00%> (+<0.01%)	⬆️

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