[pallet-revive] block.timestamps should return seconds (#7784)

In solidity `block.timestamp` should be expressed in seconds
see
https://docs.soliditylang.org/en/latest/units-and-global-variables.html#block-and-transaction-properties

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Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Alexander Theißen <alex.theissen@me.com>