Make `select` and `oc.select` more robust about omegaconf HOT 2 OPEN

from dataclasses import dataclass

from omegaconf import OmegaConf, II


cfg1 = OmegaConf.create({"a": "${oc.select:..member, 5}"})
print(cfg1.a)  # this raises an Error because of the missing node


@dataclass
class Config:
    a: int = II("${oc.select:..member, 5}")


cfg2 = OmegaConf.structured(Config)
print(cfg2.a)  # this raises an Error too