Invalid block exceptions logged as errors

[heifner]

Currently invalid (including unlinkable, out-of-order) blocks received and pushed into the controller are logged as error. Since invalid blocks from the network cause no harm as they are properly discarded, seems we should log these "errors" as info level logs, not error level logs.

Example:

error 2024-04-25T11:44:34.372 nodeos    producer_plugin.cpp:796       operator()           ] Exception on block 163: 3030001 unlinkable_block_exception: Unlinkable block
unlinkable block 000000a3ee4fa651bbcc477acccc5f96ed7c6fd32997277ce0f20fe8a4d78563 previous 000000a2ba874feef32fa22d019bd5b8a8c4211ed48f8c19cb9ba2371a65d17c
    {"id":"000000a3ee4fa651bbcc477acccc5f96ed7c6fd32997277ce0f20fe8a4d78563","p":"000000a2ba874feef32fa22d019bd5b8a8c4211ed48f8c19cb9ba2371a65d17c"}
    chain-1  controller.cpp:3792 operator()