image option source offers golden images whose import failed #4553

The VM image picker offers golden images whose import failed. imageProvider in pkg/registry/core/option/providers.go lists every PVC in cozy-public whose name starts with vm-default-images- and never looks at the DataVolume that owns it. CDI creates the PVC when the import starts, so the list includes images that are still importing and images whose DataVolume is in phase Failed.

A still-importing image is fine to offer: CDI holds a clone until the source is populated. A Failed one is not. Once #4392 lands, vm-disk refuses to render a new disk on a Failed golden and names the image, so a user who picks it from the list gets an error on create for an option the platform just offered.

The provider could read the vm-default-images-* DataVolumes in cozy-public instead of the PVCs and skip those in phase Failed.