Dynamic Admission Control: clarify exactly when failure policy Ignore is considered

I just observed that request the k8s API server can fail by rejecting admission controller even when the failure policy is ignore. It would be nice the documentation here to be enhanced and clearly state when the Ignore policy is used.

Particularly, it would be nice to be clarified which errors are unrecognized in this explanation:

failurePolicy defines how unrecognized errors and timeout errors from the admission webhook are handled.

A brief discussion on this subject matter can be found here