Revert "Check for parent of first ready block being on chain (#1812)" (#1950)
This reverts https://github.com/paritytech/polkadot-sdk/pull/1812 until we know why it causes syncing issues reported in https://github.com/subspace/subspace/issues/2122.
This reverts https://github.com/paritytech/polkadot-sdk/pull/1812 until we know why it causes syncing issues reported in https://github.com/subspace/subspace/issues/2122.