Align label generation and apply on container-source as well

[matzew]

Proposed Changes

• as per title

Pre-review Checklist

• At least 80% unit test coverage
• E2E tests for any new behavior
• Docs PR for any user-facing impact
• Spec PR for any new API feature
• Conformance test for any change to the spec

Release Note

Docs

[codecov]

Codecov Report

Attention: Patch coverage is 69.23077% with 4 lines in your changes missing coverage. Please review.

Project coverage is 64.26%. Comparing base (545c14c) to head (3767a19).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/reconciler/integration/helper.go	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8355      +/-   ##
==========================================
- Coverage   64.27%   64.26%   -0.02%     
==========================================
  Files         390      389       -1     
  Lines       23279    23281       +2     
==========================================
- Hits        14963    14961       -2     
- Misses       7522     7526       +4     
  Partials      794      794              

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[pierDipi]

/lgtm

[knative-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: matzew, pierDipi

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