✨ MachineHealthCheck supports checking Machine conditions

[justinmir]

What this PR does / why we need it:
MachineHealthCheck currently only allows checking Node conditions to validate if a machine is healthy. However, machine conditions capture conditions that do not exist on nodes, for example, control plane node conditions such as EtcdPodHealthy, SchedulerPodHealthy that can indicate if a controlplane machine has been created correctly.

Adding support for Machine conditions enables us to perform remediation during control plane upgrades.

This PR introduces a new fieldas part of the MachineHealthCheckSpec:
UnhealthyMachineConditions

This will mirror the behavior of UnhealthyNodeConditions but the MachineHealthCheck controller will instead check the machine conditions.

Which issue(s) this PR fixes:
Fixes #5450

Label(s) to be applied
/kind feature
/area machinehealthcheck

Notes for Reviewers
We updated the tests to validate the new MachineHealthCheck code paths for UnhealthyMachineConditions in the following ways:

• internal/controllers/machinehealthcheck/machinehealthcheck_controller_test.go includes a new envtest
• internal/controllers/machinehealthcheck/machinehealthcheck_targets_test.go includes a unit test that the machine will need remediation.
• Remaining test changes are boilerplate to ensure that this doesn't break existing functionality, everyplace we use UnhealthyNodeConditions we also specify a UnhealthyMachineConditions.
• Fuzz tests are updated for old APIs to drop the UnhealthyMachineConditions field since this is not specified in old APIs.

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[k8s-ci-robot]

Hi @justinmir. Thanks for your PR.

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[sbueringer]

/ok-to-test

[sbueringer]

Currently not enough bandwidth for a full review, but a few quick comments already:

• we should only add this to v1beta2
• we have to add this in a few places. I would recommend to rebase on top of main and search for all occurences of "nodeUnhealthyConditions" and check in which places we also need "unhealthyMachineConditions" (it will be in a lot of these cases :))

[justinmir]

/area machinehealthcheck

[k8s-ci-robot]

PR needs rebase.

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