[release-0.17] 🐛 Reintroduce AddMetricsServerExtraHandler on manager

[k8s-infra-cherrypick-robot]

This is an automated cherry-pick of #2813

/assign vincepri

[vincepri]

/retest

[vincepri]

/approve
/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 8aa24970d5aa7d7e0943cce21b9ca1c1c5dc2f32

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: k8s-infra-cherrypick-robot, vincepri

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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-controller-runtime-apidiff-release-0-17	2f0c2eb	link	false	/test pull-controller-runtime-apidiff-release-0-17

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