refactor: remove hpa modified from packager

[phillebaba]

Description

This change removes the hpa modified property from packager. Instead it will always set the registry to the expected scale policy no matter if it has been modified or not. The additional API calls are worth the reduction in complexity.

A note for the future is that the purpose for disabling scale down of the registry has to be documented. It is not totally clear why this is done.

Related Issue

Relates to #2694

Checklist before merging

• Test, docs, adr added or updated as needed
• Contributor Guide Steps followed

[netlify]

✅ Deploy Preview for zarf-docs canceled.

Name	Link
🔨 Latest commit	b334201
🔍 Latest deploy log	https://app.netlify.com/sites/zarf-docs/deploys/66853949b2e46500081a40b6

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 13 lines in your changes missing coverage. Please review.

Project coverage is 19.00%. Comparing base (43e50bb) to head (b334201).

Files	Patch %	Lines
src/pkg/packager/deploy.go	0.00%	9 Missing ⚠️
src/pkg/cluster/zarf.go	0.00%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2696      +/-   ##
==========================================
- Coverage   19.00%   19.00%   -0.01%     
==========================================
  Files         170      170              
  Lines       12199    12200       +1     
==========================================
  Hits         2318     2318              
+ Misses       9595     9594       -1     
- Partials      286      288       +2     

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