apply default certificate again in cases of invalid or incomplete cert config

[kdomanski]

Fixes #4628

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[alvaroaleman]

/ok-to-test

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Codecov Report

❗ No coverage uploaded for pull request base (master@67dce30). Click here to learn what that means.
The diff coverage is 0%.

@@            Coverage Diff            @@
##             master    #4816   +/-   ##
=========================================
  Coverage          ?   58.49%           
=========================================
  Files             ?       88           
  Lines             ?     6717           
  Branches          ?        0           
=========================================
  Hits              ?     3929           
  Misses            ?     2362           
  Partials          ?      426

Impacted Files	Coverage Δ
internal/ingress/controller/template/template.go	80.24% <ø> (ø)
internal/ingress/controller/controller.go	50.3% <0%> (ø)

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[ElvinEfendi]

@kdomanski please also include e2e tests to make sure this bug does not get reintroduced.

[aledbf]

/approve

[ElvinEfendi]

The tests for the second and third scenarios are missing but this is already a lot better than what we have in master 🎉

/lgtm

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, ElvinEfendi, kdomanski

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