fix: use flagset when initializing klog

[hairyhum]

Issue Reference

NA

Description

When using kargo as a library, logger will initialize klog in the init() function with default flagset. This means that if any other tool initializes the klog with default flagset in the main() function, that will panic with flag redefined error.

klog recommends calling InitFlags in main() or using a flagset. This PR uses a "kargo_logger" flagset for InitFlags

Checklist

• The PR is linked to an existing issue.
• The linked issue has no blocking labels (kind/proposal,
  needs discussion, needs research, maintainer only, area/security,
  size/large, size/x-large, size/xx-large).
• I have added or updated tests as appropriate.
• I have added or updated documentation as appropriate.

AI Use Disclosure

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• This PR was written by a human without AI assistance.
• This PR was written by a human with AI assistance. A human has reviewed every line prior to opening the PR.
• This PR was written by an AI with human supervision. A human has reviewed every line prior to opening the PR.
• This PR was written entirely by AI. No human has reviewed this prior to opening the PR.

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[kargo-governance-bot]

Automated Policy Notice

This pull request has been converted to a draft because it does not reference an unblocked issue. Maintainers do not routinely review drafts.

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To move forward:

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[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 58.05%. Comparing base (4caa1ee) to head (bb2cab2).

Files with missing lines	Patch %	Lines
pkg/logging/logger.go	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6329   +/-   ##
=======================================
  Coverage   58.05%   58.05%           
=======================================
  Files         499      499           
  Lines       41748    41749    +1     
=======================================
+ Hits        24238    24239    +1     
  Misses      16050    16050           
  Partials     1460     1460           

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[krancour]

@hairyhum you're supposed to be exempt from the PR policy. Not sure what happened, but I will find out and fix it.

[EronWright]

LGTM, but let me wait for non-draft