Full node stops receiving gossiped blocks when disconnected from sequencer

[srene]

When a full node disconnects from the sequencer, it does not reconnect to it unless the node is restarted, when there are only two nodes. Need to check if it happens when there are more nodes.

[srene]

After a few checks, it seems nodes are reconnecting automatically after approx 2 minutes, but it needs more investigation to see if it happens in all cases and why after 2 minutes.

[srene]

Kad-dht libp2p implementation runs a periodic check that, if not enough peers on routing tables, it bootstraps again. The process reruns every 2 minute, according to the bootstrap config parameter here:
https://github.com/libp2p/go-libp2p-kad-dht/blob/bdca14419ec5f7ad0790f17856964bb99bee7436/dht_bootstrap.go#L20

it does not seem to be externally configurable.
Therefore it seems in the worse case, a full node will be disconnected during 2 minutes and it will connect again automatically.

[srene]

Extra notes about DHT and peer discovery here
https://www.notion.so/dymension/Dymint-peer-discovery-draft-67bffeeeb13f4a1790a64767c1141f00?pvs=4

[srene]

PR #556 adds a new function to periodically check if a full node is not connected to other nodes and bootstraps the DHT again to reconnect to sequencer.