fix: panic in MachinePool log

[mweibel]

What type of PR is this? /kind bug

What this PR does / why we need it: Fixes a panic when trying to delete a machine where there is no OwnerMachine available anymore. The log statement was wrong in that it didn't specify a key for the value.

Special notes for your reviewer: partial panic log - note, the line numbers are a bit off since I'm running on a fork containing multiple changes which will be submitted as separate PRs today

panic: runtime error: hash of unhashable type v1beta1.AzureMachinePoolMachine [recovered]
       panic: runtime error: hash of unhashable type v1beta1.AzureMachinePoolMachine
manager
goroutine 623 [running]:
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile.func1()
       /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.17.3/pkg/internal/controller/controller.go:116 +0x1e5
panic({0x2c8dae0?, 0xc001f6ad70?})
       /usr/local/go/src/runtime/panic.go:914 +0x21f
k8s.io/klog/v2/internal/serialize.MergeKVs({0xc002170120, 0x12, 0x0?}, {0xc009c69cc0, 0x2, 0xc0023c4cf0?})
       /go/pkg/mod/k8s.io/klog/v2@v2.120.1/internal/serialize/keyvalues.go:82 +0x134
k8s.io/klog/v2.(*klogger).Info(0xc00088d740, 0x2, {0x328e1ca, 0x33}, {0xc009c69cc0?, 0x40e578?, 0x2cd9ae0?})
       /go/pkg/mod/k8s.io/klog/v2@v2.120.1/klogr.go:56 +0x5a
sigs.k8s.io/cluster-api-provider-azure/util/tele.(*compositeLogSink).Info.func1(...)
       /workspace/util/tele/composite_logger.go:54
sigs.k8s.io/cluster-api-provider-azure/util/tele.(*compositeLogSink).iter(...)
       /workspace/util/tele/composite_logger.go:48
sigs.k8s.io/cluster-api-provider-azure/util/tele.(*compositeLogSink).Info(0xc000079000?, 0x2, {0x328e1ca, 0x33}, {0xc009c69cc0, 0x2, 0x2})
       /workspace/util/tele/composite_logger.go:53 +0x69
github.com/go-logr/logr.Logger.Info({{0x36a7338?, 0xc00a631da0?}, 0x0?}, {0x328e1ca, 0x33}, {0xc009c69cc0, 0x2, 0x2})
       /go/pkg/mod/github.com/go-logr/logr@v1.4.2/logr.go:280 +0xdc
sigs.k8s.io/cluster-api-provider-azure/azure/scope.(*MachinePoolScope).DeleteMachine(_, {_, _}, {{{0x29501e6, 0x17}, {0xc00213ced0, 0x27}}, {{0xc000dd2470, 0x9}, {0x0, ...}, ...}, ...})
       /workspace/azure/scope/machinepool.go:552 +0x45f
sigs.k8s.io/cluster-api-provider-azure/exp/controllers.(*AzureMachinePoolReconciler).reconcileDelete(0xc0005a54a0, {0x36a0b70?, 0xc0003b9ce0?}, 0xc0006cdef0, {0x36e00d8, 0xc006dd2000})
       /workspace/exp/controllers/azuremachinepool_controller.go:413 +0x850
sigs.k8s.io/cluster-api-provider-azure/exp/controllers.(*AzureMachinePoolReconciler).Reconcile(0xc0005a54a0, {0x36a0ac8?, 0xc008ef0210?}, {{{0xc000caaa40?, 0xa?}, {0xc000caaab7?, 0x0?}}})
       /workspace/exp/controllers/azuremachinepool_controller.go:254 +0xb45
sigs.k8s.io/cluster-api-provider-azure/pkg/coalescing.(*reconciler).Reconcile(0xc0003ea400, {0x36a0ac8?, 0xc008ef0150?}, {{{0xc000caaa40?, 0x0?}, {0xc000caaab7?, 0xc001c77d08?}}})
       /workspace/pkg/coalescing/reconciler.go:109 +0x3eb
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile(0x36a6298?, {0x36a0ac8?, 0xc008ef0150?}, {{{0xc000caaa40?, 0xb?}, {0xc000caaab7?, 0x0?}}})
       /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.17.3/pkg/internal/controller/controller.go:119 +0xb7

• [x] cherry-pick candidate

TODOs:

• [x] squashed commits
• [ ] includes documentation
• [ ] adds unit tests

Release note:

NONE

[k8s-ci-robot]

Hi @mweibel. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[jackfrancis]

/ok-to-test

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 62.19%. Comparing base (44e0cd5) to head (749cb25). Report is 6 commits behind head on main.

Files	Patch %	Lines
azure/scope/machinepool.go	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #4942 +/- ## ======================================= Coverage 62.19% 62.19% ======================================= Files 201 201 Lines 16884 16884 ======================================= Hits 10501 10501 Misses 5592 5592 Partials 791 791 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[nawazkh]

/lgtm Thank you

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 48780b30570491447b6bc5ab2aca7a3c5c8f5817

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mboersma

The full list of commands accepted by this bot can be found here.

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