Bor gpo.ignoreprice should be aligned with txpool.pricelimit

[dahu33]

When running Polygon Mainnet nodes using the provided config in this repository, the txpool.pricelimit (minimum gas price limit to enforce acceptance into the pool) is set to 30000000000 but the gpo.ignoreprice (gas price below which the gas price oracle will ignore transactions) is left to its default value of 2.

Because some validators on the network include transactions with gas price under 30 Gwei, the nodes gas price oracle may return a value under 30 Gwei when called with the JSON RPC eth_maxPriorityFeePerGas.

This is a recurring issue we've seen across many node providers leading to many transactions being rejected with the error {"code":-32000,"message":"transaction underpriced"} (when using the node gas price oracle).

The nodes gpo.ignoreprice and txpool.pricelimit settings should be aligned to remove the discrepancy between the minimum gas tip/priority price that nodes are willing to accept a transaction at and the suggested gas tip/priority price that nodes return.

I have shared a bit more details in a blog post here: https://www.curvegrid.com/blog/2022-11-21-polygon-transaction-underpriced