Add a private service name helper and use throughout

[markusthoemmes]

Proposed Changes

By popular demand, this adds a helper function to generate the private service name and makes use of it throughout the codebase.

Release Note

NONE

/assign @julz @vagababov

[codecov]

Codecov Report

Merging #11176 (b416311) into main (fc6ca85) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main   #11176   +/-   ##
=======================================
  Coverage   87.69%   87.69%           
=======================================
  Files         190      191    +1     
  Lines        9194     9195    +1     
=======================================
+ Hits         8063     8064    +1     
+ Misses        877      876    -1     
- Partials      254      255    +1     

Impacted Files	Coverage Δ
pkg/activator/handler/handler.go	95.65% <100.00%> (ø)
...onciler/serverlessservice/resources/names/names.go	100.00% <100.00%> (ø)
...reconciler/serverlessservice/resources/services.go	100.00% <100.00%> (ø)
.../reconciler/serverlessservice/serverlessservice.go	93.25% <100.00%> (ø)
pkg/autoscaler/statforwarder/leases.go	76.97% <0.00%> (-1.44%)	⬇️
pkg/activator/net/revision_backends.go	91.32% <0.00%> (+0.91%)	⬆️

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[julz]

/lgtm

[markusthoemmes]

/approve

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: julz, markusthoemmes

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Details

Needs approval from an approver in each of these files:

• pkg/activator/OWNERS [julz,markusthoemmes]
• pkg/reconciler/OWNERS [markusthoemmes]
• pkg/testing/OWNERS [julz,markusthoemmes]

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