Remove vesitigial showCertExpiration

[imnasnainaec]

Remove unused variable that's no longer needed since #377 closed.

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This change is 

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.40%. Comparing base (1a493f1) to head (0ca3f19).
⚠️ Report is 34 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3982   +/-   ##
=======================================
  Coverage   74.40%   74.40%           
=======================================
  Files         291      291           
  Lines       10790    10790           
  Branches     1351     1351           
=======================================
  Hits         8028     8028           
  Misses       2373     2373           
  Partials      389      389           

Flag	Coverage Δ
backend	85.45% <ø> (ø)
frontend	65.86% <ø> (ø)

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[jasonleenaylor]

@jasonleenaylor reviewed 5 of 5 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)

[jasonleenaylor]

@jasonleenaylor reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)