[BUG] Create TiDB cluster panic in controller transform

[nayutah]

Describe the bug
When create a TiDB cluster with 0.9.0, controller transformer paniced.

To Reproduce
Steps to reproduce the behavior:

1. git checkout -b tidb origin/feat/tidb-addon-revamp
2. sed -e 's/v7.1.2/v7.1.5/g'
3. helm template tidb | kubectl apply -f -
4. helm template tidb-cluster | kubectl apply -f -

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
2024-05-16T17:30:24.107Z INFO Starting workers {"controller": "clusterversion", "controllerGroup": "apps.kubeblocks.io", "controllerKind": "ClusterVersion", "worker count": 1}
2024-05-16T17:30:24.112Z INFO Starting workers {"controller": "cluster", "controllerGroup": "apps.kubeblocks.io", "controllerKind": "Cluster", "worker count": 2}
2024-05-16T17:30:24.113Z INFO Starting workers {"controller": "componentversion", "controllerGroup": "apps.kubeblocks.io", "controllerKind": "ComponentVersion", "worker count": 1}
2024-05-16T17:30:24.113Z INFO Starting workers {"controller": "clusterdefinition", "controllerGroup": "apps.kubeblocks.io", "controllerKind": "ClusterDefinition", "worker count": 1}
2024-05-16T17:30:24.113Z INFO Starting workers {"controller": "componentdefinition", "controllerGroup": "apps.kubeblocks.io", "controllerKind": "ComponentDefinition", "worker count": 1}
2024-05-16T17:30:24.122Z INFO Observed a panic in reconciler: runtime error: invalid memory address or nil pointer dereference {"controller": "cluster", "controllerGroup": "apps.kubeblocks.io", "controllerKind": "Cluster", "Cluster": {"name":"release-name-tidb-cluster","namespace":"default"}, "namespace": "default", "name": "release-name-tidb-cluster", "reconcileID": "5c2db182-084e-43dd-bce6-c1f66ae341fd"}
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x24aaff1]

goroutine 803 [running]:
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile.func1()
/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.17.2/pkg/internal/controller/controller.go:116 +0x1e5
panic({0x2849fa0?, 0x4b1c990?})
/usr/local/go/src/runtime/panic.go:914 +0x21f
github.com/apecloud/kubeblocks/controllers/apps.(*clusterBackupPolicyTransformer).Transform.func2({0xc001f60770, {0xc00105e648, 0x4}, 0x0, {0xc00105e648, 0x4}}, 0xc001f67520, 0x0)
/src/controllers/apps/transformer_cluster_backup_policy.go:162 +0x251
github.com/apecloud/kubeblocks/controllers/apps.(*clusterBackupPolicyTransformer).Transform(0xc001f3dc80, {0x32f6078?, 0xc000fde6e0?}, 0xc0019f9170)
/src/controllers/apps/transformer_cluster_backup_policy.go:181 +0x6f2
github.com/apecloud/kubeblocks/pkg/controller/graph.TransformerChain.ApplyTo({0xc000a56c00?, 0x10, 0x4b6ccc0?}, {0x32f6078, 0xc000fde6e0}, 0xc000aa78f0?)
/src/pkg/controller/graph/transformer.go:57 +0x9b
github.com/apecloud/kubeblocks/controllers/apps.(*clusterPlanBuilder).Build(0xc000ac3270)
/src/controllers/apps/cluster_plan_builder.go:174 +0x12f
github.com/apecloud/kubeblocks/controllers/apps.(*ClusterReconciler).Reconcile(0xc000424540, {0x32f6430, 0xc00133f440}, {{{0xc000fa1ff6, 0x7}, {0xc000444440, 0x19}}})
/src/controllers/apps/cluster_controller.go:162 +0x85c
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile(0x32fc648?, {0x32f6430?, 0xc00133f440?}, {{{0xc000fa1ff6?, 0xb?}, {0xc000444440?, 0x0?}}})
/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.17.2/pkg/internal/controller/controller.go:119 +0xb7
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler(0xc000cb6280, {0x32f6468, 0xc000ac2230}, {0x2986e60?, 0xc001003700?})
/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.17.2/pkg/internal/controller/controller.go:316 +0x3cc
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem(0xc000cb6280, {0x32f6468, 0xc000ac2230})
/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.17.2/pkg/internal/controller/controller.go:266 +0x1af
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2()
/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.17.2/pkg/internal/controller/controller.go:227 +0x79
created by sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2 in goroutine 119
/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.17.2/pkg/internal/controller/controller.go:223 +0x565

Desktop (please complete the following information):
Kubernetes: v1.29.4+k3s1
KubeBlocks: 0.9.0-beta.25
kbcli: 0.8.2
WARNING: version difference between kbcli (0.8.2) and kubeblocks (0.9.0-beta.25)

[free6om]