fix panic on GetHostFromConfigEndpoint

[kobzonega]

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Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Issue Number: N/A

What is the new behavior?

• fix panic on GetHostFromConfigEndpoint

Other information

panic: interface conversion: interface {} is []interface {}, not []schema.Host [recovered]
	panic: interface conversion: interface {} is []interface {}, not []schema.Host

goroutine 689 [running]:
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile.func1()
	/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.14.1/pkg/internal/controller/controller.go:119 +0x1fa
panic({0x1b4f8c0, 0xc003a9d800})
	/usr/local/go/src/runtime/panic.go:884 +0x213
github.com/ydb-platform/ydb-kubernetes-operator/api/v1alpha1.(*Storage).GetHostFromConfigEndpoint(0xc000bbe2c0)
	/workspace/api/v1alpha1/storage_webhook.go:69 +0x177