Prevent the case of an empty replicas in high-availability

[houshengbo]

No description provided.

[codecov]

Codecov Report

Merging #1137 (a580e97) into main (c92cd54) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1137   +/-   ##
=======================================
  Coverage   79.06%   79.06%           
=======================================
  Files          35       35           
  Lines        1519     1519           
=======================================
  Hits         1201     1201           
  Misses        232      232           
  Partials       86       86           

Impacted Files	Coverage Δ
pkg/reconciler/common/ha.go	59.09% <100.00%> (ø)

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[maximilien]

/approve
/lgtm

[knative-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: houshengbo, maximilien

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