[release-0.19] 🐛 Refactor certificate watcher to use polling, instead of fsnotify

[k8s-infra-cherrypick-robot]

This is an automated cherry-pick of #3020

/assign vincepri

[m-messiah]

/approve
/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: d413ca52394d17463a54ec3c911a442cef4abf46

[vincepri]

@m-messiah seems like there is a null pointer exception in the tests on this release branch

[m-messiah]

@m-messiah seems like there is a null pointer exception in the tests on this release branch

The test introduces the new check that uses golang 1.23 feature, while this release is tested in go 1.22.

I pushed a bugfix with backwards compatible test: #3026

[vincepri]

/approve
/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 5f501e3b5122827d350d208740bf24f826d9308f

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: k8s-infra-cherrypick-robot, m-messiah, 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-0-19	56d6cb0	link	false	/test pull-controller-runtime-apidiff-release-0-19

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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[vincepri]

/cherry-pick release-0.18

[k8s-infra-cherrypick-robot]

@vincepri: #3023 failed to apply on top of branch "release-0.18":

Applying: Reestablish watch for the certificate paths
Applying: Remove fsnotify and use cached read watcher
Using index info to reconstruct a base tree...
M	examples/scratch-env/go.mod
M	examples/scratch-env/go.sum
M	go.mod
Falling back to patching base and 3-way merge...
Auto-merging go.mod
CONFLICT (content): Merge conflict in go.mod
Auto-merging examples/scratch-env/go.sum
CONFLICT (content): Merge conflict in examples/scratch-env/go.sum
Auto-merging examples/scratch-env/go.mod
CONFLICT (content): Merge conflict in examples/scratch-env/go.mod
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0002 Remove fsnotify and use cached read watcher

In response to this:

/cherry-pick release-0.18

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