`BlockId` removal: `BlockBuilderProvider::new_block_at` (#6734)

* `BlockId` removal: `BlockBuilderProvider::new_block_at`

It changes the arguments of `BlockBuilderProvider::new_block_at` from:
`BlockId<Block>` to: `Block::Hash`

* useless import removed

* update lockfile for {"substrate"}

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Co-authored-by: parity-processbot <>