Type Alias ErasValidatorPrefs

ErasValidatorPrefs: StorageDescriptor<[number, SS58String], {
    blocked: boolean;
    commission: number;
}, false>

Similar to ErasStakers, this holds the preferences of validators.

This is keyed first by the era index to allow bulk deletion and then the stash account.

Is it removed after [Config::HistoryDepth] eras.