[cherry-pick][release-1.9] Add labels for velero installed namespace to support PSA

[blackpiglet]

Add labels for created namespace during the Velero installation to adopt k8s v1.25's PSS and PSA.

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Fixes #(issue)

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[codecov-commenter]

Codecov Report

Merging #5887 (145a91f) into release-1.9 (2f97356) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@               Coverage Diff               @@
##           release-1.9    #5887      +/-   ##
===============================================
+ Coverage        41.66%   41.67%   +0.01%     
===============================================
  Files              214      214              
  Lines            18600    18605       +5     
===============================================
+ Hits              7749     7754       +5     
  Misses           10268    10268              
  Partials           583      583              

Impacted Files	Coverage Δ
pkg/install/resources.go	53.63% <100.00%> (+1.07%)	⬆️

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