Bad MachineSet prevent all other MachineSets from scaling activities

Issue

• When creating a new MachineSet with a improperly formatted label for the new nodes, new Machines (for any MachineSet) are not able to be created.
• An error like below is repeating constantly in Machine API Controller Pod logs (Controller Manager container):

I0623 00:07:44.820556       1 reflector.go:158] Listing and watching *v1beta1.MachineSet from sigs.k8s.io/controller-runtime/pkg/cache/internal/informers_map.go:204
E0623 00:07:44.823162       1 reflector.go:123] sigs.k8s.io/controller-runtime/pkg/cache/internal/informers_map.go:204: Failed to list *v1beta1.MachineSet: v1beta1.MachineSetList.Items: []v1beta1.MachineSet: v1beta1.MachineSet.Spec: v1beta1.MachineSetSpec.Template: v1beta1.MachineTemplateSpec.Spec: v1beta1.MachineSpec.ProviderSpec: v1beta1.ProviderSpec.ObjectMeta: v1.ObjectMeta.Labels: ReadString: expects " or n, but found 4, error found in #10 byte of ...|:{"test":4}},"provid|..., bigger context ...|data":{"creationTimestamp":null,"labels":{"test":4}},"providerSpec":{"value":{"ami":{"id":"ami-0f0fa|...