pallets: implement `Default` for `GenesisConfig` in `no_std` (#7271)

* pallets: implement Default for GenesisConfig in no_std

This change is follow-up of: https://github.com/paritytech/substrate/pull/14108

It is a step towards: https://github.com/paritytech/substrate/issues/13334

* Cargo.lock updated

* update lockfile for {"substrate"}

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Co-authored-by: parity-processbot <>