Fix RPC proxy middleware errors showing up in logs

[zone117x]

Expected-looking http errors occurring inside the RPC proxy are showing up as level: error logs.

Example: Response 400 during POST /v2/transaction to extra endpoint http://stacks-node-follower-events-blue-0.stacks-node-follower-events-blue.prod-stacks.svc.cluster.local:20443/v2/transactions

[MHassanTariq]

@zone117x what is the required behavior for this issue? With the current approach, the specified error is logged here. Are we supposed to ignore the http error even if the p.value.ok is not true? Or should such errors be shown as level: warning logs?

[zone117x]

These should probably be warning level logs.