[release-1.20] Bump cert-manager to v1.19.1

[mboersma]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Manual cherry-pick of #5922.

Updates cert-manager to the current release v1.19.1 to sync with CAPI.

Which issue(s) this PR fixes:

N/A, but see #5910 for prior art.

Special notes for your reviewer:

TODOs:

• squashed commits
• includes documentation
• adds unit tests
• cherry-pick candidate

Release note:

NONE

[k8s-ci-robot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 52.80%. Comparing base (f80d0cb) to head (b8f62ac).
⚠️ Report is 3 commits behind head on release-1.20.

Additional details and impacted files

@@               Coverage Diff                @@
##           release-1.20    #5925      +/-   ##
================================================
- Coverage         52.81%   52.80%   -0.01%     
================================================
  Files               279      279              
  Lines             29602    29602              
================================================
- Hits              15634    15632       -2     
- Misses            13154    13156       +2     
  Partials            814      814              

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[jackfrancis]

/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 413441f85a2e25669208d412577f0735c373d8de

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jackfrancis

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