[release-1.8] 🌱Bump cert-manager to 1.16.1

[k8s-infra-cherrypick-robot]

This is an automated cherry-pick of #11322

/assign sbueringer

[sbueringer]

/area clusterctl
/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 515da8dda5d57254e8679b6690ca12842ece6999

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: sbueringer

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[k8s-ci-robot]

@k8s-infra-cherrypick-robot: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-cluster-api-apidiff-release-1-8	7aae687	link	false	/test pull-cluster-api-apidiff-release-1-8

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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