fix: Fix timestamp of genesis block

[dima74]

Context

Currently, genesis block might be created with time equal to genesis transaction creation time. We have invariant that "transaction creation time" < "block creation time" (added in #4928), so this will result in error:

thread 'tokio-runtime-worker' panicked at crates/iroha_core/src/kura.rs:331:14:
INTERNAL BUG: Failed to decode block: ParityScale("Could not decode `SignedBlock::V1.0`:\n\tCould not decode `SignedBlockCandidate::payload`:\n\t\tTransaction creation time is ahead of block creation time\n")

Solution

Ensure that genesis block time is at least 1 millisecond ahead of genesis transaction time.

Checklist

• I've read CONTRIBUTING.md.
• (optional) I've written unit tests for the code changes.
• All review comments have been resolved.
• All CI checks pass.