`block export` (or any sub command) starts a BFT mining coordinator

[matthew1001]

Description

When running the block export or block import commands, a BFT mining coordinator is started. If the node is the only validator is will continue to produce new blocks even during export/import.

Acceptance Criteria

Don't start a mining coordinator when running any of the sub-commands

Steps to Reproduce (Bug)

Run besu --genesis-file=../genesis.json --data-path=./data blocks export --to=blocks.bin. If the node is the only validator it will produce new blocks during the export