Kpa support scale subresource

[thiagomedina]

Fixes #15528

Proposed Changes

• Use the Kubernetes /scale subresource to read and patch replica count

Release Note

[knative-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: thiagomedina
Once this PR has been reviewed and has the lgtm label, please assign dsimansk for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[codecov]

Codecov Report

❌ Patch coverage is 71.42857% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.18%. Comparing base (0c341d4) to head (7378056).

Files with missing lines	Patch %	Lines
pkg/reconciler/autoscaling/kpa/scaler.go	71.42%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #16419      +/-   ##
==========================================
- Coverage   80.20%   80.18%   -0.02%     
==========================================
  Files         217      217              
  Lines       13511    13506       -5     
==========================================
- Hits        10836    10830       -6     
- Misses       2310     2311       +1     
  Partials      365      365              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.