Level 5 chain can get in a case where it doesn't verifiy/finalize a publicly broadcasted block

[cheeseandcereal]

• Dragonchain Version: 4.2.0
• Entrypoint: txn_processor

On an L5, the check_confirmations method exists at the end of transaction processor execution in order to check the public network for confirmations of the last broadcasted L5 block.

If there is any issue checking confirmations for this block, the method is set to essentially ignore this, and simply try to check again next run of the transaction processor.

The problem comes here:

dragonchain/dragonchain/transaction_processor/level_5_actions.py

Line 176 in 64c25f4

last_confirmed_block = get_last_confirmed_block()

If an L5 were to get into a state where it's unable to check for confirmations all the way until it creates another block, it will simply 'forget' to check for confirmations from the old block, because it is hard-coded to only check for confirmations of (and subsequently close/out finalize) the most recently created block.

This needs to be fixed so that check_confirmations can check all unconfirmed blocks, not just the most recent one.